TY - JOUR A1 - Khare, V. A1 - Li, Z. A1 - Mantion, Alexandre A1 - Ayi, A. A. A1 - Sonkaria, S. A1 - Voelkl, A. A1 - Thünemann, Andreas A1 - Taubert, A. T1 - Strong anion effects on gold nanoparticle formation in ionic liquids N2 - Ionic liquids (ILs) have attracted tremendous interest in the recent past for their potential in many chemical fields. The current report explores the effects of a set of ILs based on the 1-ethyl-3-methyl-imidazolium cation and different anions on the formation of gold nanoparticles. X-Ray diffraction finds face-centered cubic gold in all cases, but transmission electron microscopy (TEM) shows that there are distinct differences in particle formation and stabilization with the ethyl sulfate (ES), trifluoromethanesulfonate (TfO) and methanesulfonate (MS) anions. With the MS anion, nanoparticles with diameters between 5 and 7 nm form, which increasingly aggregate at higher reaction temperatures. With TfO, also small 5 to 7 nm particles form, but only at low temperatures. Above ca. 160 °C, large, ill-defined and aggregated particles form. With ES, polydisperse samples form at all temperatures except 160 °C. In this case the nanoparticles appear often surrounded by an IL film, which appears to stabilize individual, ca. 15 to 20 nm particles. Dynamic light scattering and UV/Vis spectroscopy further show that in suspension the particles are, much like seen in the TEM, more strongly aggregated with higher reaction temperatures. In summary, the results suggest that there are very specific IL-gold interactions that are responsible for the formation of gold particles with an IL-specific shape, size, and aggregation behavior. KW - Ionic liquid templating KW - Gold nanoparticle KW - Ionic liquid PY - 2010 DO - https://doi.org/10.1039/b917467b SN - 0959-9428 SN - 1364-5501 VL - 20 SP - 1332 EP - 1339 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-20872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Khare, V. A1 - Kraupner, A. A1 - Mantion, Alexandre A1 - Jelicic, A. A1 - Thünemann, Andreas A1 - Giordano, C. A1 - Taubert, A. T1 - Stable iron carbide nanoparticle dispersions in [Emim][SCN] and [Emim][N(CN)2] ionic liquids N2 - Dispersions of Fe3C nanoparticles in several ionic liquids (ILs) have been investigated. The ILs are based on 1-ethyl-3-methylimidazolium [Emim] and 1-butyl-3-methylimidazolium [Bmim] cations. Anions are ethylsulfate [ES], methanesulfonate [MS], trifluoromethylsulfonate (triflate) [TfO], tetrafluoroborate [BF4], dicyanamide [N(CN)2], and thiocyanate [SCN]. Among the ILs studied, [Emim][SCN] and [Emim][N(CN)2] stand out because only in these ILs have stable and transparent nanoparticle dispersions been obtained. All other ILs lead to blackish, slightly turbid dispersions or to completely nontransparent suspensions, which often contain undispersed sediment. UV/vis spectroscopy, transmission electron microscopy, and X-ray scattering suggest that the reason for the stabilization of the Fe3C nanoparticles in [Emim][SCN] is the leaching of traces of iron from the particles (without affecting the crystal structure of the Fe3C particles). The resulting particle surface is thus carbon-rich, which presumably favors the stabilization of the particles. A similar explanation can be postulated for [Emim][N(CN)2], with the dicyanamide anion also being a good ligand for iron. KW - Ionic liquid KW - Iron carbide PY - 2010 DO - https://doi.org/10.1021/la100775m SN - 0743-7463 SN - 1520-5827 VL - 26 IS - 13 SP - 10600 EP - 10605 PB - American Chemical Society CY - Washington, DC AN - OPUS4-21624 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Graf, P. A1 - Mantion, Alexandre A1 - Foelske, A. A1 - Shkilnyy, A. A1 - Masic, A. A1 - Thünemann, Andreas A1 - Taubert, A. T1 - Peptide-coated silver nanoparticles: Synthesis, surface chemistry, and pH-triggered, reversible assembly into particle assemblies N2 - Simple tripeptides are scaffolds for the synthesis and further assembly of peptide/silver nanoparticle composites. Herein, we further explore peptide-controlled silver nanoparticle assembly processes. Silver nanoparticles with a pH-responsive peptide coating have been synthesized by using a one-step precipitation/coating route. The nature of the peptide/silver interaction and the effect of the peptide on the formation of the silver particles have been studied via UV/Vis, X-ray photoelectron, and surface-enhanced Raman spectroscopies as well as through electron microscopy, small angle X-ray scattering and powder X-ray diffraction with Rietveld refinement. The particles reversibly form aggregates of different sizes in aqueous solution. The state of aggregation can be controlled by the solution pH value. At low pH values, individual particles are present. At neutral pH values, small clusters form and at high pH values, large precipitates are observed. KW - Hybrid materials KW - Nano-particles KW - Oligopeptides KW - pH KW - Silver PY - 2009 DO - https://doi.org/10.1002/chem.200802329 SN - 0947-6539 SN - 1521-3765 VL - 15 IS - 23 SP - 5831 EP - 5844 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-19514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Thünemann, Andreas A1 - Eckelt, J. A1 - Maskos, Michael A1 - Wolf, B. A. ED - Matyjaszewski, K. ED - Möller, M. T1 - Fractionation N2 - The enormous diversity of polymers with respect to molecular weight, molecular architecture, and – in the case of copolymers – also the content and arrangement of dissimilar monomers requires well-targeted methods for the separation of the different species that are contained in a given sample. This chapter presents the most abundant fractionation procedures, which are either based on thermodynamic driving forces (like in the case of liquid–liquid phase separation) or on kinetic effects (as with field-flow fractionation). KW - Field-flow fractionation KW - Polymer science KW - Asymmetrical flow field-flow fractionation (AF-FFF) KW - Baker-Williams fractionation KW - Chemical composition distribution (CCD) KW - Circular asymmetrical flow field-flow eluation (CAFFFE) KW - Continuous polymer fractionation (CPF) KW - Crystallization analysis fractionation (CRYSTAF) KW - Crystallization–dissolution fractionation (CDF) KW - Liquid-liquid phase separation KW - Temperature rising elution fractionation (TREF) KW - Phase distribution chromatography (PDC) PY - 2012 SN - 978-0-444-53349-4 DO - https://doi.org/10.1016/B978-0-444-53349-4.00022-4 VL - 2 IS - Chapter 2.04 SP - 65 EP - 91 PB - Elsevier CY - Amsterdam AN - OPUS4-26265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fenger, A. A1 - Fertitta, E. A1 - Kirmse, H. A1 - Thünemann, Andreas A1 - Rademann, K. T1 - Size dependent catalysis with CTAB-stabilized gold nanoparticles N2 - CTAB-stabilized gold nanoparticles were synthesized by applying the seeding-growth approach in order to gain information about the size dependence of the catalytic reduction of p-nitrophenol to p-aminophenol with sodium borohydride. Five different colloidal solutions of stabilized gold nanoparticles have been characterized by TEM, AFM, UV-Vis, SAXS, and DLS for their particle size distributions. Gold nanoparticles (mean sizes: 3.5, 10, 13, 28, 56 nm diameter) were tested for their catalytic efficiency. Kinetic data were acquired by UV-Vis spectroscopy at different temperatures between 25 and 45 °C. By studying the p-nitrophenol to p-aminophenol reaction kinetics we determined the nanoparticle size which is needed to gain the fastest conversion under ambient conditions in the liquid phase. Unexpectedly, CTAB-stabilized gold nanoparticles with a diameter of 13 nm are most efficient. KW - Nanoparticle KW - Small-angle X-ray scattering KW - SAXS PY - 2012 DO - https://doi.org/10.1039/c2cp40792b SN - 1463-9076 SN - 1463-9084 VL - 14 IS - 26 SP - 9343 EP - 9349 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-26071 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeng, Y. A1 - Grandner, S. A1 - Oliveira, C.L.P. A1 - Thünemann, Andreas A1 - Paris, O. A1 - Pedersen, J. S. A1 - Klapp, S.H.L. A1 - von Klitzing, R. T1 - Effect of particle size and Debye length on order parameters of colloidal silica suspensions under confinement N2 - Using atomic force microscopy (AFM) and small angle X-ray scattering (SAXS), we show a full comparison between structuring of nanoparticles in confinement and in bulk in order to explain the effect of confinement on characteristic lengths and the scaling law of the characteristic lengths. Three different-sized particle suspensions are used to check the generalization and the correlation between the characteristic lengths and the system parameters, like particle diameter and Debye length. The two characteristic lengths obtained from AFM force curves, the oscillatory wavelength λ, which is related to the average particle distance, and the decay length ξ, which measures how far particle correlates to obtain periodic oscillations, are in good agreement with the mean particle distance 2π/qmax and the correlation length 2/Δq in bulk, respectively, obtained from the structure peaks of SAXS diagrams. Although confinement causes layering of nanoparticles parallel to the confining surfaces, the characteristic lengths in the direction perpendicular to the confining surfaces follow the bulk behavior. The wavelength scales as ρ-1/3 with the particle number density ρ irrespective of the particle size and the ionic strength and shows a pure volume effect. Upon comparing with literature results, the λ = ρ-1/3 scaling law can be applied more generally for charged particles, as long as the repulsive interaction is sufficiently long-ranged, than the previous expression of λ = 2(R + κ-1), which only approaches the value of average particle distance under specific conditions. The decay length ξ is controlled both by the particle size and the ionic strength of the suspensions, and ξ = R + κ-1 is proposed in the paper. In addition, the interaction strength, the force amplitude and maximum scattering intensity, increases linearly with particle concentration. On the other hand, the Monte Carlo (MC) simulations and approximate hypernetted chain (HNC) closure calculation based on Derjaguin-Landau-Verwey-Overbeek (DLVO) potential are employed to study the characteristic lengths from the theoretical point of view. The experimental wavelengths are in good agreement with the theoretical counterparts and the experimental decay lengths show the same qualitative behavior as theoretical ones on the particle size and ionic strength. KW - Nanoparticle PY - 2011 DO - https://doi.org/10.1039/c1sm05971h SN - 1744-683X VL - 7 IS - 22 SP - 10899 EP - 10909 PB - RSC Publ. CY - Cambridge AN - OPUS4-24660 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lak, A. A1 - Thünemann, Andreas A1 - Schilling, M. A1 - Ludwig, F. T1 - Resolving particle size modality in bi-modal iron oxide nanoparticle suspensions N2 - Particle size modality in bi-modal iron oxide suspensions was resolved by exploiting complex ac-susceptibility (ACS), small angle X-ray scattering (SAXS) and photon cross-correlation spectroscopy. To explain dynamic magnetic response of bi-modal suspensions, the Debye model was expanded to a linear superposition form allowing for the contribution of both particle fractions. This modified and adopted model is able to resolve the bi-modal particle size distributions. The SAXS curves of mono- and bi-modal suspensions were fitted well using a Monte Carlo simulation scheme, allowing the detection of bi-modal particle size distributions with high precision. KW - Iron oxide nanoparticle KW - Bi-modal size distribution characterization KW - Complex ac-susceptibility KW - Small angle X-ray scattering KW - Modeling KW - Nanotechnology KW - SAXS KW - Nanoparticles PY - 2015 DO - https://doi.org/10.1016/j.jmmm.2014.08.050 SN - 0304-8853 VL - 380 SP - 140 EP - 143 PB - Elsevier CY - Amsterdam AN - OPUS4-32563 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kraus, Werner A1 - Pitarch López, J. A1 - Thünemann, Andreas A1 - Kurth, D.G. T1 - The crystal structure of the homoleptic iron(II) complex of the novel 4'-(4'''-pyridyl-N-oxide)-2,2':6',2''-terpyridine ligand T2 - Gemeinsame Jahrestagung Deutsche Gesellschaft für Kristallographie und Nationalkomitee für Kristallographie der Österreichischen Akademie der Wissenschaften CY - Cologne, Germany DA - 2005-02-28 PY - 2005 SN - 0930-486X SP - 107 PB - Oldenbourg CY - München AN - OPUS4-7272 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thünemann, Andreas A1 - Kubowicz, S. A1 - Geue, T. M. A1 - Pietsch, U. A1 - Watson, M. D. A1 - Tchebotareva, N. A1 - Müllen, K. T1 - X-ray reflectivity study of an amphiphilic hexa-peri-hexabenzocoronene at a structured silicon wafer surface KW - Discotic Liquid Crystals KW - Thin Organic Films PY - 2003 DO - https://doi.org/10.1021/la035210e SN - 0743-7463 SN - 1520-5827 VL - 19 IS - 26 SP - 10997 EP - 10999 PB - American Chemical Society CY - Washington, DC AN - OPUS4-2846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Looking at the Nanoscale in Life Science: Applications of Small-Angle X-Ray Scattering T2 - Seminar Informatik und Mikrosystemtechnik CY - Kaiserslautern, Germany DA - 2014-10-09 PY - 2014 AN - OPUS4-31607 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sieg, H. A1 - Braeuning, C. A1 - Kunz, B. M. A1 - Daher, H. A1 - Kästner, C. A1 - Krause, B.-C. A1 - Meyer, T. A1 - Jalili, P. A1 - Kogeveen, K. A1 - Böhmert, L. A1 - Lichtenstein, D. A1 - Burel, A. A1 - Chevance, S. A1 - Jungnickel, H. A1 - Tentschert, J. A1 - Laux, P. A1 - Braeuning, A. A1 - Gauffre, F. A1 - Fessard, V. A1 - Meijer, J. A1 - Estrela-Lopis, I. A1 - Thünemann, Andreas A1 - Luch, A. A1 - Lampen, A. T1 - Uptake and molecular impact of aluminum-containing nanomaterials on human intestinal caco-2 cells N2 - Aluminum (Al) is one of the most common elements in the earth crust and increasingly used in food, consumer products and packaging. Its hazard potential for humans is still not completely understood. Besides the metallic form, Al also exists as mineral, including the insoluble oxide, and in soluble ionic forms. Representatives of these three species, namely a metallic and an oxidic species of Al-containing nanoparticles and soluble aluminum chloride, were applied to human intestinal cell lines as models for the intestinal barrier. We characterized physicochemical particle parameters, protein corona composition, ion release and cellular uptake. Different in vitro assays were performed to determine potential effects and molecular modes of Action related to the individual chemical species. For a deeper insight into signaling processes, microarray transcriptome analyses followed by bioinformatic data analysis were employed. The particulate Al species showed different solubility in biological media. Metallic Al nanoparticles released more ions than Al2O3 nanoparticles, while AlCl3 showed a mixture of dissolved and agglomerated particulate entities in biological media. The protein corona composition differed between both nanoparticle species. Cellular uptake, investigated in transwell experiments, occurred predominantly in particulate form, whereas ionic Al was not taken up by intestinal cell lines. Transcellular transport was not observed. None of the Al species showed cytotoxic effects up to 200 mg Al/mL. The transcriptome analysis indicated mainly effects on oxidative stress pathways, xenobiotic metabolism and metal homeostasis. We have shown for the first time that intestinal cellular uptake of Al occurs preferably in the particle form, while toxicological effects appear to be ion-related. KW - Small-angle x-ray scattering KW - SAXS KW - Nanopatricle PY - 2018 DO - https://doi.org/10.1080/17435390.2018.1504999 SN - 1743-5390 VL - 12 IS - 9 SP - 992 EP - 1013 PB - Taylor & Francis AN - OPUS4-47432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haase, A. A1 - Tentschert, J. A1 - Jungnickel, H. A1 - Graf, P. A1 - Mantion, Alexandre A1 - Draude, F. A1 - Plendl, J. A1 - Goetz, M.E. A1 - Galla, S. A1 - Masic, A. A1 - Thünemann, Andreas A1 - Taubert, A. A1 - Arlinghaus, H. F. A1 - Luch, A. T1 - Toxicity of silver nanoparticles in human macrophages: uptake, intracellular distribution and cellular responses N2 - Silver nanoparticles (SNP) are among the most commercialized nanoparticles worldwide. They can be found in many diverse products, mostly because of their antibacterial properties. Despite its widespread use only little data on possible adverse health effects exist. It is difficult to compare biological data from different studies due to the great variety in sizes, coatings or shapes of the particles. Here, we applied a novel synthesis approach to obtain SNP, which are covalently stabilized by a small peptide. This enables a tight control of both size and shape. We applied these SNP in two different sizes of 20 or 40 nm (Ag20Pep and Ag40Pep) and analyzed responses of THP-1-derived human macrophages. Similar gold nanoparticles with the same coating (Au20Pep) were used for comparison and found to be non-toxic. We assessed the cytotoxicity of particles and confirmed their cellular uptake via transmission electron microscopy and confocal Raman microscopy. Importantly a majority of the SNP could be detected as individual particles spread throughout the cells. Furthermore we studied several types of oxidative stress related responses such as induction of heme oxygenase I or formation of protein carbonyls. In summary, our data demonstrate that even low doses of SNP exerted adverse effects in human macrophages. KW - Silver nanoparticles KW - Neurotoxicology KW - Protein carbonyls KW - ROS PY - 2011 DO - https://doi.org/10.1088/1742-6596/304/1/012030 SN - 1742-6588 SN - 1742-6596 VL - 304 SP - 012030-1 - 012030-14 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-24035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sieg, H. A1 - Lehmann, C. A1 - Kästner, Claudia A1 - Krause, B. A1 - Burel, A. A1 - Chevance, S. A1 - Böhmert, L. A1 - Lichtenstein, D. A1 - Tentschert, J. A1 - Bräuning, A. A1 - Laux, A. A1 - Thünemann, Andreas A1 - Loipis, I. E. A1 - Fessard, V. A1 - Luch, A. A1 - Lampen, A. T1 - Effects of Al-, Ti- and Zn-containing nanomaterials on cell lines in vitro N2 - Among the different tested endpoints, Al- and Ticontaining nanomaterials did notshowany toxicity in intestinal cell lines in vitro. Nevertheless, this absence of effect was not due to an absence of exposure, since particle-specific uptake was reported. Metal particle uptake over a long time period might therefore be relevant for risk assessment of aluminum- and titanium-containing food products. T2 - 52nd Congress of the European-Societies-of-Toxicology (EUROTOX) CY - Seville, Spain DA - 04.09.2017 KW - Nanoparticles PY - 2017 DO - https://doi.org/10.1016/j.toxlet.2016.06.1954 SN - 0378-4274 VL - 258 SP - S272 PB - Elsevier Ltd. AN - OPUS4-40939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Buzanich, Günter A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Thünemann, Andreas A1 - Streli, C. T1 - Impurities in multicrystalline silicon wafers for solar cells detected by synchrotron micro-beam X-ray fluorescence analysis N2 - We report on the trace analysis of copper and iron impurities in multicrystalline silicon wafers with the microbeam X-ray fluorescence (µ-XRF) technique. The efficiency of solar cells, which are based on multicrystalline silicon wafers, is strongly influenced by minor contamination with metals such as copper and iron. Application of compound refractive lenses (CRLs) in µ-XRF allows versatile two-dimensional mapping of relevant contaminations and localization of their sites of deposition. In this context, the measured bulk average limit of detection (LOD) was one picogram of iron and copper per gram of silicon. We suggest that µ-XRF is a valuable tool for non-destructive spatial (3D) quantification of metal impurities in a wide range of materials and devices whose functioning could be critically affected by impurities. KW - X-ray micro beam KW - Compound refractive lens KW - Solar cell KW - Silicon impurities PY - 2012 DO - https://doi.org/10.1039/c2ja30188a SN - 0267-9477 SN - 1364-5544 VL - 27 IS - 11 SP - 1875 EP - 1881 PB - Royal Society of Chemistry CY - London AN - OPUS4-26791 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Polte, Jörg A1 - Kraehnert, R. A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Thünemann, Andreas A1 - Emmerling, Franziska T1 - New insights of the nucleation and growth process of gold nanoparticles via in situ coupling of SAXS and XANES N2 - Although metallic nanoparticles play an important role in the area of nanotechnology, a coherent mechanistic explanation for the evolution of the particles during their chemical synthesis has not yet been provided in many cases. To gain a profound understanding of the growth mechanism of colloidal nanoparticles, new approaches using Small Angle X-Ray Scattering (SAXS) combined with X-ray absorption near-edge structure (XANES) are presented. This combination allows for insights into two prominent syntheses routes of gold nanoparticles (GNP): The 'slow' reaction using sodium citrate (30-90 min) as a reducing agent and the 'fast' reaction employing NaBH4 (within few seconds). In the first case data derived with the coupled XANES and SAXS suggests a four-step particle formation mechanism. For the second system a time resolution in the order of 100-200 ms was achieved by coupling a common laboratory SAXS instrument with a microstructured mixer, which allows data acquisition in a continuous-flow mode. The results indicate a coalescence driven growth process. Based on the capabilities to deduce the size, number and polydispersity of the particles, the results of both methods enable the development of mechanistic schemes explaining the different phases of particle formation and growth, thus providing a basis for improved control over the synthesis processes. KW - SAXS KW - XANES KW - Nanoparticle formation PY - 2010 DO - https://doi.org/10.1088/1742-6596/247/1/012051 SN - 1742-6588 SN - 1742-6596 VL - 247 IS - 1 SP - 012051-1 - 012051-10 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-22684 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Polte, Jörg A1 - Emmerling, Franziska A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Thünemann, Andreas T1 - Real-time monitoring of copolymer stabilized growing gold nanoparticles N2 - A great challenge in the production of nanoparticles with defined sizes and properties is to control their growth in situ. We developed a dedicated combined small-angle X-ray scattering (SAXS) and X-ray absorption spectroscopy (XAS) setup to monitor nanoparticle formation in solution. The capabilities of simultaneously deriving particle sizes and oxidation states of atoms/ions are illustrated for the formation of spherical gold nanoparticles by the reduction of hydrogen tetrachloroaureate (HAuCl4). Particles with initial radii of 4.60 ± 0.10 nm and final radii of 5.67 ± 0.10 nm were produced in a levitated droplet with a volume of 4 µL. An ethylene oxide/propylene oxide triblock copolymer PEO-PPO-PEO (Pluronic F-127) functions as reducing agent and colloidal stabilizer. XANES shows in situ how the gold was reduced in the droplet from Au(III) to Au(0), and simultaneously SAXS recorded the size distribution of the formed nanoparticles. It is shown that the final particle number is reached quickly. Thereafter, only the particles’ sizes increase. Comparison of XANES and SAXS shows that the quantity of Au(0) is higher than the quantity of gold located in the nanoparticles while the particles are growing. Finally, all the Au(0) is found in the nanoparticles. We tentatively attribute this finding to the pseudo crown ether effect of the polymer surfactant that kinetically stabilizes gold atoms when formed from gold ions within their protecting cavity. A simple “burst” mechanism for the gold nanoparticle formation is the consequence. The possibility of an inhomogeneous particles structure with an enhanced density near the particle surface is discussed. PY - 2010 DO - https://doi.org/10.1021/la903829q SN - 0743-7463 SN - 1520-5827 VL - 26 IS - 8 SP - 5889 EP - 5894 PB - American Chemical Society CY - Washington, DC AN - OPUS4-21223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - (Bio)polymers tune the catalytic activity of silver nanoparticles N2 - We report on the development of ultra-small core-shell silver nanoparticles synthesized by an up-scaled modification of the polyol process. It is foreseen to use these thoroughly characterized particles as reference material to compare the catalytic and biological properties of functionalized silver nanoparticles. Small-angle X-ray scattering (SAXS) analysis reveal a narrow size distribution of the silver cores with a mean radius of RC = 3.0 nm and a distribution width of 0.6 nm. Dynamic light scattering (DLS) provides a hydrodynamic radius of RH = 10.0 nm and a PDI of 0.09. The particles’ surface is covered with poly(acrylic acid) (PAA) forming a shell with a thickness of 7.0 nm, which provides colloidal stability lasting for more than six months at ambient conditions. The PAA can be easily exchanged by biomolecules to modify the surface functionality. Replacements of PAA with glutathione (GSH) and bovine serum albumin (BSA) have been performed as examples. We demonstrate that the particles effectively catalyze the reduction of 4-nitrophenol to 4-aminophenol with sodium borohydride. The tunable catalytic activity of (436 ± 24) L g-1 s-1 is the highest reported in literature for silver nanoparticles. T2 - POLYDAYS 2016 CY - Potsdam, Germany DA - 28.09.2016 KW - Nanoparticles KW - Small-angle X-ray scattering KW - SAXS KW - Silver PY - 2016 AN - OPUS4-37622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Nanomaterial Characterization - Aspects from Standardization T2 - First BfR-Academy Training School on Nanotechnologies for Risk Assessors CY - BfR Federal Institute for Risk Assessment (Berlin, Germany) DA - 2015-03-02 PY - 2015 AN - OPUS4-32712 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Resolving Particles Size Distributions in Bi- and Trimodal Nanoparticle Suspensions T2 - 16th International Conference on Small-Angle Scattering CY - Technical University Berlin (Berlin, Germany) DA - 2015-09-13 PY - 2015 AN - OPUS4-34352 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Characterization of silver nanoparticles in cell culture medium containing fetal bovine serum N2 - Nanoparticles are being increasingly used in consumer products worldwide, and their toxicological effects are currently being intensely debated. In vitro tests play a significant role in nanoparticle risk assessment, but reliable particle characterization in the cell culture medium with added fetal bovine serum (CCM) used in these tests is not available. As a step toward filling this gap, we report on silver ion release by silver nanoparticles, and changes in the particle radii and in their protein corona when incubated in CCM. Particles of a certified reference material (CRM), p1, and particles of a commercial silver nanoparticle material, p2, were investigated. The colloidal stability of p1 is provided by the surfactants polyethylene glycole-25 glyceryl trioleate and polyethylene glycole-20 sorbitan monolaurate, whereas p2 is stabilized by polyvinylpyrrolidone (PVP). Dialysis of p1 and p2 reveal that their silver ion release rates in CCM are much larger than in water. Particle characterization was performed with asymmetrical flow field-flow fractionation (FFF), small-angle X-ray scattering (SAXS), dynamic light scattering (DLS) and electron microscopy. p1 and p2 have similar hydrodynamic radii of 15 nm and 16 nm, respectively. The silver core radii are 9.2 and 10.2 nm. Gel electrophoresis and subsequent peptide identification reveal that albumin is the main corona component of p1 and p2 after incubation in CCM, which consists of Dulbeccos Modified Eagle Medium with 10% fetal bovine serum added. T2 - 6th International Colloids Conference CY - Berlin, Germany DA - 19.06.2016 KW - SAXS KW - Nanoparticle KW - Silver KW - Albumin PY - 2016 AN - OPUS4-36639 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Risse, Kerstin A1 - Nikiforidis, Constantinos V. A1 - Morris, Imogen A1 - Thünemann, Andreas A1 - Drusch, Stephan T1 - Regulating the heat stability of protein-phospholipid stabilised oil-water emulsions by changing the phospholipid headgroup or fatty acyl chain N2 - Stabilising oil–water emulsions remains a central challenge across food, pharmaceutical and cosmetic applications. β-lactoglobulin (β-LG) and phospholipids (PLs) can act synergistically at oil-water interfaces: PLs adsorb rapidly, while β-LG forms a viscoelastic protein network that enhances long-term stability. However, competitive adsorption between proteins and PLs can disrupt interfacial structure. In addition, for commercial production, emulsions are often exposed to heat treatment during or after manufacture, for instance due to food safety requirements. Yet, the combined effects of PL structure and heat treatment on interfacial organisation and emulsion stability remain poorly understood. Here we show that PL saturation and processing temperature jointly determine interfacial organisation, protein-PL interactions and emulsion stability. Using β-LG-PL emulsions, we combined ζ-potential measurements, small-angle X-ray scattering (SAXS), micro-differential scanning calorimetry (μDSC), X-ray diffraction and confocal laser scanning microscopy (CLSM) to link interfacial composition with functional stability. Below the β-LG denaturation temperature (≤75 °C), saturated PLs promoted partial unfolding of β-LG at the interface without displacement, producing mixed protein-PL networks with enhanced viscoelasticity and stability. Unsaturated PLs displaced β-LG, yielding less elastic interfaces and promoting protein aggregation in the bulk. At ≥75 °C, increased hydrophobicity intensified protein-protein interactions irrespective of PL type. Our findings reveal that saturated PLs shift the β-LG denaturation temperature upward by restricting molecular mobility, without preventing quaternary-level protein-protein interactions. Thermal denaturation, regardless of PL type, promoted interfacial multilayer formation at 90 °C. These results provide a mechanistic framework for tailoring emulsion stability via lipid saturation and processing temperature. KW - Small-angle X-ray scattering KW - SAXS KW - Nanostructure KW - Reference Method KW - Colloid KW - Nanoparticle PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648956 DO - https://doi.org/10.1016/j.jcis.2025.139530 SN - 0021-9797 VL - 705 SP - 1 EP - 25 PB - Elsevier Inc. AN - OPUS4-64895 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, R.H. A1 - Runge, S. A1 - Ravelli, V. A1 - Mehnert, W. A1 - Thünemann, Andreas A1 - Souto, E.B. T1 - Oral bioavailability of cyclosporine: Solid lipid nanoparticles (SLN®) versus drug nanocrystals N2 - For the development of an optimized oral formulation for cyclosporine A, 2% of this drug has been formulated in solid lipid nanoparticles (SLN™, mean size 157 nm) and as nanocrystals (mean size 962 nm). The encapsulation rate of SLN was found to be 96.1%. Nanocrystals are composed of 100% of drug. For the assessment of the pharmacokinetic parameters the developed formulations have been administered via oral route to three young pigs. Comparison studies with a commercial Sandimmun Neoral/Optoral® used as reference have been performed. The blood profiles observed after oral administration of the commercial microemulsion Sandimmun® revealed a fast absorption of drug leading to the observation of a plasma peak above 1000 ng/ml within the first 2 h. For drug nanocrystals most of the blood concentrations were in the range between 30 and 70 ng/ml over a period of 14 h. These values were very low, showing huge differences between the measuring time points and between the tested animals. On the contrary, administration of cyclosporine-loaded SLN led to a mean plasma profile with almost similarly low variations in comparison to the reference microemulsion, however with no initial blood peak as observed with the Sandimmun Neoral/Optoral®. Comparing the area under the curves (AUC) obtained with the tested animals it could be stated that the SLN™ formulation avoids side effects by lacking blood concentrations higher than 1000 ng/ml. In this study it has been proved that using SLN™ as a drug carrier for oral administration of cyclosporine A a low variation in bioavailability of the drug and simultaneously avoiding the plasma peak typical of the first Sandimmun® formulation can be achieved. KW - Solid lipid nanoparticles KW - SLN KW - Drug nanocrystals KW - Sandimmun Neoral/Optoral KW - Oral administration PY - 2006 DO - https://doi.org/10.1016/j.ijpharm.2006.02.045 SN - 0378-5173 SN - 1873-3476 VL - 317 IS - 1 SP - 82 EP - 89 PB - Elsevier CY - Amsterdam AN - OPUS4-12464 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kubowicz, S. A1 - Thünemann, Andreas A1 - Weberskirch, R. A1 - Möhwald, H. T1 - Cylindrical Micelles of alpha-Fluorocarbon-omega-Hydrocarbon End-Capped Poly(N-acylethylene imine)s N2 - Micelles of ABC block copolymers with varying degrees of polymerization of the B block (n) and constant lengths of the A and C blocks were investigated by small-angle X-ray scattering (SAXS), analytical ultracentrifugation (AUC), surface tension measurements, and isothermal titration calorimetry. The copolymers consisting of hydrophilic poly(N-acylethylene imine)s, end-capped with a hydrophobic fluorocarbon and a hydrocarbon block, are polymeric surfactants ( = 35 mN/m). They form cylindrical micelles with radii of 3.0 nm (n = 35), 3.8 nm (n = 57), and 4.0 nm (n = 72). Their lengths are about 20 nm. The micelles can be doped with 1,4-diiodoperfluorobutane for the polymers with n = 57 and 72 but not for n = 35. We assume that the doped micelles form distinct fluorocarbon domains, which are able to incorporate selectively the fluorocarbon dopant. The work presented here is a contribution to the development of multicompartment micelles. KW - Micelles KW - Small-angle X-ray scattering PY - 2005 DO - https://doi.org/10.1021/la050987o SN - 0743-7463 SN - 1520-5827 VL - 21 IS - 16 SP - 7214 EP - 7219 PB - American Chemical Society CY - Washington, DC AN - OPUS4-10380 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Juling, S. A1 - Niedzwiecka, A. A1 - Böhmert, L. A1 - Lichtenstein, D. A1 - Selve, S. A1 - Braeuning, A. A1 - Thünemann, Andreas A1 - Krause, E. A1 - Lampen, A. T1 - Protein Corona Analysis of Silver Nanoparticles Links to Their Cellular Effects N2 - The breadth of applications of nanoparticles and the access to food-associated consumer products containing nanosized materials lead to oral human exposure to such particles. In biological fluids nanoparticles dynamically interact with biomolecules and form a protein corona. Knowledge about the protein corona is of great interest for understanding the molecular effects of particles as well as their fate inside the human body. We used a mass spectrometry-based toxicoproteomics approach to elucidate mechanisms of toxicity of silver nanoparticles and to comprehensively characterize the protein corona formed around silver nanoparticles in Caco-2 human intestinal epithelial cells. Results were compared with respect to the cellular function of proteins either affected by exposure to nanoparticles or present in the protein corona. A transcriptomic data set was included in the analyses in order to obtain a combined multiomics view of nanoparticle-affected cellular processes. A relationship between corona proteins and the proteomic or transcriptomic responses was revealed, showing that differentially regulated proteins or transcripts were engaged in the same cellular signaling pathways. Protein corona analyses of nanoparticles in cells might therefore help in obtaining information about the molecular consequences of nanoparticle treatment. KW - Silver nanoparticles KW - Protein KW - Small-angle X-ray scattering KW - SAXS PY - 2017 DO - https://doi.org/10.1021/acs.jproteome.7b00412 SN - 1535-3893 SN - 1535-3907 VL - 16 IS - 11 SP - 4020 EP - 4034 PB - Americal Chemical Society AN - OPUS4-42688 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Prause, A. A1 - Hormann, A. A1 - Cristiglio, V. A1 - Smales, Glen Jacob A1 - Thünemann, Andreas A1 - Gradzielski, M. A1 - Findenegg, G. H. T1 - Incorporation and structural arrangement of microemulsion droplets in cylindrical pores of mesoporous silica N2 - The behaviour of microemulsion (ME) droplets in mesoporous systems is highly important for understanding the immobilisation of drugs or chemical formulations, cleaning processes or enhanced oil recovery. The loading of pores as well as the structural organisation of MEs within the pores is a relevant parameter, especially for immobilisation applications. For this reason, the uptake of microemulsions in cylindrical pores of SBA-15 was investigated via adsorption and small-angle neutron scattering (SANS). Adsorption isotherms revealed an adsorption of the microemulsion droplets based on the adsorption of surfactant as a driving force. The adapted scattering model is based on the analysis of bare SBA-15 in full contrast conditions and employs microemulsions inside of SBA-15 measured at the silica contrast matching point. Accordingly, the structural arrangement of microemulsion droplets in the pores of SBA-15 was determined in good detail. Microemulsion droplets smaller than the pore size access the pores while retaining their spherical shape and become increasingly ordered for higher loading, where the droplets arrange in a dense packing of spherical droplets in a cylindrical pore. Interestingly, microemulsion droplets larger than the pore size can easily be incorporated, but become deformed upon entering and are present as elongated rod-like structures. KW - Mesoporous Silica KW - SAXS KW - Microemulsion PY - 2021 DO - https://doi.org/10.1080/00268976.2021.1913255 VL - 119 IS - 15-16 SP - 13255 PB - Taylor & Francis AN - OPUS4-52959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tentschert, J. A1 - Draude, F. A1 - Jungnickel, H. A1 - Haase, A. A1 - Mantion, Alexandre A1 - Galla, S. A1 - Thünemann, Andreas A1 - Taubert, A. A1 - Luch, A. A1 - Arlinghaus, H. F. T1 - TOF-SIMS analysis of cell membrane changes in functional impaired human macrophages upon nanosilver treatment N2 - Silver nanoparticles (SNP) are among the most commercialized nanoparticles. Here, we show that peptide-coated SNP cause functional impairment of human macrophages. A dose-dependent inhibition of phagocytosis is observed after nanoparticle treatment, and pretreatment of cells with N-acetyl cysteine (NAC) can counteract the phagocytosis disturbances caused by SNP. Using the surface-sensitive mode of time-of-flight secondary ion mass spectrometry, in combination with multivariate statistical methods, we studied the composition of cell membranes in human macrophages upon exposure to SNP with and without NAC preconditioning. This method revealed characteristic changes in the lipid pattern of the cellular membrane outer leaflet in those cells challenged by SNP. Statistical analyses resulted in 19 characteristic ions, which can be used to distinguish between NAC pretreated and untreated macrophages. The present study discusses the assignments of surface cell membrane phospholipids for the identified ions and the resulting changes in the phospholipid pattern of treated cells. We conclude that the adverse effects in human macrophages caused by SNP can be partially reversed through NAC administration. Some alterations, however, remained. KW - Silver nanoparticles KW - Lipidomics KW - N-acetyl cysteine KW - Phagocytosis KW - Oxidative stress KW - Reference material PY - 2013 DO - https://doi.org/10.1002/sia.5155 SN - 0142-2421 SN - 1096-9918 VL - 45 IS - 1 SP - 483 EP - 485 PB - Wiley CY - Chichester AN - OPUS4-27586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lutz, J.-F. A1 - Thünemann, Andreas A1 - Nehring, R. T1 - Preparation by Controlled Radical Polymerization and Self-Assembly via Base-Recognition of Synthetic Polymers Bearing Complementary Nucleobases N2 - The radical polymerization of three monomers bearing nucleobases 1-(4-vinylbenzyl)thymine (VBT), 1-(4-vinylbenzyl)uracil (VBU) and 9-(4-vinylbenzyl)adenine (VBA) was investigated. The corresponding homopolymers could be prepared in high yields via conventional radical polymerization. However, the resulting polymers were found to be only soluble in a few polar solvents. On the other hand, copolymers of dodecyl methacrylate (DMA) with either VBT or VBA could be prepared via both free radical polymerization and atom transfer radical polymerization and could be dissolved in a large variety of organic solvents. Moreover, the formed complementary copolymers P(VBT-co-DMA) and P(VBA-co-DMA) were found to self-assemble in dilute solutions in dioxane or chloroform via base recognition, as evidenced by a significant hypochromicity effect in UV spectroscopy. Nevertheless, at higher concentrations in chloroform, both dynamic light scattering and optical microscopy indicate that P(VBT-co-DMA), P(VBA-co-DMA), or P(VBT-co-DMA)/P(VBA-co-DMA) mixtures spontaneously self-assemble into micron size spherical aggregates. 1H NMR and FTIR studies confirmed that the self-assembly process is driven in all cases via H-bond formation. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4805-4818, 2005 KW - ATRP KW - Living polymerization KW - Nucleic acids KW - Polymersomes KW - Self-assembly PY - 2005 DO - https://doi.org/10.1002/pola.20976 SN - 0360-6376 SN - 0887-624X VL - 43 IS - 20 SP - 4805 EP - 4818 PB - Wiley CY - Hoboken, NJ AN - OPUS4-10842 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Poyraz, Ö. A1 - Schmidt, H. A1 - Seidel, K. A1 - Delißen, Friedmar A1 - Ader, C. A1 - Tenenboim, H. A1 - Goosmann, C. A1 - Laube, B. A1 - Thünemann, Andreas A1 - Zychlinsky, A. A1 - Baldus, M. A1 - Lange, A. A1 - Griesinger, C. A1 - Kolbe, M. T1 - Protein refolding is required for assembly of the type three secretion needle N2 - Pathogenic Gram-negative bacteria use a type three secretion system (TTSS) to deliver virulence factors into host cells. Although the order in which proteins incorporate into the growing TTSS is well described, the underlying assembly mechanisms are still unclear. Here we show that the TTSS needle protomer refolds spontaneously to extend the needle from the distal end. We developed a functional mutant of the needle protomer from Shigella flexneri and Salmonella typhimurium to study its assembly in vitro. We show that the protomer partially refolds from α-helix into β-strand conformation to form the TTSS needle. Reconstitution experiments show that needle growth does not require ATP. Thus, like the structurally related flagellar systems, the needle elongates by subunit polymerization at the distal end but requires protomer refolding. Our studies provide a starting point to understand the molecular assembly mechanisms and the structure of the TTSS at atomic level. PY - 2010 DO - https://doi.org/10.1038/nsmb.1822 SN - 1545-9993 SN - 1545-9985 VL - 17 SP - 788 EP - 792 PB - Nature Publ. Comp. CY - New York, NY, USA AN - OPUS4-21726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thünemann, Andreas A1 - Gruber, Alexandra A1 - Klinger, Daniel T1 - Amphiphilic Nanogels: Fuzzy Spheres with a Pseudo-Periodic Internal Structure N2 - Amphiphilic polymer nanogels (NGs) are promising drug delivery vehicles that extend the application of conventional hydrophilic NGs to hydrophobic cargoes. By randomly introducing hydrophobic groups into a hydrophilic polymer network, loading and release profiles as well as surface characteristics of these colloids can be tuned. However, very little is known about the underlying internal structure of such complex colloidal architectures. Of special interest is the question how the amphiphilic network composition influences the internal morphology and the “fuzzy” surface structure. To shine light into the influence of varying network amphiphilicity on these structural features, we investigated a small library of water-swollen amphiphilic NGs using small-angle X-ray scattering (SAXS). It was found that overall hydrophilic NGs, consisting of pure poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA), display a disordered internal structure as indicated by the absence of a SAXS peak. In contrast, a SAXS peak is present for amphiphilic NGs with various amounts of incorporated hydrophobic groups such as cholesteryl (CHOLA) or dodecyl (DODA). The internal composition of the NGs is considered structurally homologous to microgels. Application of the Teubner–Strey model reveals that hydrophilic PHPMA NGs have a disordered internal structure (positive amphiphilicity factor) while CHOLA and DODA samples have an ordered internal structure (negative amphiphilicity factor). From the SAXS data it can be derived that the internal structure of the amphiphilic NGs consists of regularly alternating hydrophilic and hydrophobic domains with repeat distances of 3.45–5.83 nm. KW - Polymer KW - Nanoparticle KW - SAXS PY - 2020 DO - https://doi.org/10.1021/acs.langmuir.0c01812 VL - 36 IS - 37 SP - 10979 EP - 10988 PB - American Chemical Society AN - OPUS4-51302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Polte, Jörg A1 - Erler, Robert A1 - Thünemann, Andreas A1 - Emmerling, Franziska A1 - Kraehnert, R. T1 - SAXS in combination with a free liquid jet for improved time-resolved in situ studies of the nucleation and growth of nanoparticles PY - 2010 DO - https://doi.org/10.1039/c0cc03238g SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x VL - 46 IS - 48 SP - 9209 EP - 9211 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-23049 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rocha, S. A1 - Thünemann, Andreas A1 - Pereira, M.C. A1 - Coelho, M.A.N. A1 - Möhwald, H. A1 - Brezesinski, G. T1 - The Conformation of B18 Peptide in the Presence of Fluorinated and Alkylated Nanoparticles KW - Small-angle-X-ray scattering KW - Circular dichroism PY - 2005 SN - 1439-4227 SN - 1439-7633 VL - 6 SP - 1 EP - 4 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-6064 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stock, V. A1 - Fahrenson, C. A1 - Thünemann, Andreas A1 - Donmez, M. H. A1 - Voss, L. A1 - Bohmert, L. A1 - Braeuning, A. A1 - Lampen, A. A1 - Sieg, H. T1 - Impact of artificial digestion on the sizes and shapes of microplastic particles N2 - Current analyses show a widespread occurrence of microplastic particles in food products and raise the question of potential risks to human health. Plastic particles are widely considered to be inert due to their low chemical reactivity and therefore supposed to pose, if at all only minor hazards. However, variable physicochemical conditions during the passage of the gastrointestinal tract gain strong importance, as they may affect particle characteristics. This study aims to analyze the impact of the gastrointestinal passage on the physicochemical particle characteristics of the five most produced and thus environmentally relevant plastic materials polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate and polystyrene. Scanning electron microscopy (SEM) and subsequent image analysis were employed to characterize microplastic particles. Our results demonstrate a high resistance of all plastic particles to the artificial digestive juices. The present results underline that the main stages of the human gastrointestinal tract do not decompose the particles. This allows a direct correlation between the physicochemical particle characteristics before and after digestion. Special attention must be paid to the adsorption of organic compounds like proteins, mucins and lipids on plastic particles since it could lead to misinterpretations of particle sizes and shapes. KW - Artificial digestion KW - Gastrointestinal barrier KW - Microplastic KW - Oral uptake KW - Particle size PY - 2020 DO - https://doi.org/10.1016/j.fct.2019.111010 VL - 135 SP - 111010 PB - Elsevier Ltd. AN - OPUS4-49999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pauw, Brian Richard A1 - Smith, A. J. A1 - Snow, T. A1 - Terril, N. J. A1 - Thünemann, Andreas T1 - The modular small-angle X-ray scattering data correction sequence N2 - Data correction is probably the least favourite activity amongst users experimenting with small-angle X-ray scattering: if it is not done sufficiently well, this may become evident only during the data analysis stage, necessitating the repetition of the data corrections from scratch. A recommended comprehensive sequence of elementary data correction steps is presented here to alleviate the difficulties associated with data correction, both in the laboratory and at the synchrotron. When applied in the proposed order to the raw signals, the resulting absolute scattering cross section will provide a high degree of accuracy for a very wide range of samples, with its values accompanied by uncertainty estimates. The method can be applied without modification to any pinhole-collimated instruments with photon-counting direct-detection area detectors. KW - Small-angle X-ray scattering KW - SAXS KW - Accuracy KW - Methodology KW - Data correction PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-432114 DO - https://doi.org/10.1107/S1600576717015096 SN - 1600-5767 VL - 50 IS - 6 SP - 1800 EP - 1811 PB - International Union of Crystallography AN - OPUS4-43211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fuhrmann, A. A1 - Göstl, R. A1 - Wendt, R. A1 - Kötteritzsch, J. A1 - Hager, M. D. A1 - Schubert, U. S. A1 - Brademann-Jock, Kerstin A1 - Thünemann, Andreas A1 - Nöchel, U. A1 - Behl, M. A1 - Hecht, S. T1 - Conditional repair by locally switching the thermal healing capability of dynamic covalent polymers with light N2 - Healable materials could play an important role in reducing the environmental footprint of our modern technological society through extending the life cycles of consumer products and constructions. However, as most healing processes are carried out by heat alone, the ability to heal damage generally kills the parent material’s thermal and mechanical properties. Here we present a dynamic covalent polymer network whose thermal healing ability can be switched ‘on’ and ‘off’ on demand by light, thereby providing local control over repair while retaining the advantageous macroscopic properties of static polymer networks. We employ a photoswitchable furan-based crosslinker, which reacts with short and mobile maleimidesubstituted poly(lauryl methacrylate) chains forming strong covalent bonds while simultaneously allowing the reversible, spatiotemporally resolved control over thermally induced de- and re-crosslinking. We reason that our system can be adapted to more complex materials and has the potential to impact applications in responsive coatings, photolithography and microfabrication. KW - Small-angle X-ray scattering KW - SAXS KW - Polymer PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-386689 DO - https://doi.org/10.1038/ncomms13623 SN - 2041-1723 VL - 7 SP - Article 13623, 1 EP - 7 PB - NATURE PUBLISHING GROUP CY - MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND AN - OPUS4-38668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pauw, Brian Richard A1 - Kästner, Claudia A1 - Thünemann, Andreas T1 - Nanoparticle size distribution quantification: results of a small-angle X-ray scattering inter-laboratory comparison N2 - This paper presents the first worldwide inter-laboratory comparison of small-angle X-ray scattering (SAXS) for nanoparticle sizing. The measurands in this comparison are the mean particle radius, the width of the size distribution and the particle concentration. The investigated sample consists of dispersed silver nanoparticles, surrounded by a stabilizing polymeric shell of poly(acrylic acid). The silver cores dominate the X-ray scattering pattern, leading to the determination of their radius size distribution using (i) the generalized indirect Fourier transformation method, (ii) classical model fitting using SASfit and (iii) a Monte Carlo fitting approach using McSAS. The application of these three methods to the collected data sets from the various laboratories produces consistent mean number- and volume-weighted core radii of Rn = 2.76 (6) nm and Rv = 3.20 (4) nm, respectively. The corresponding widths of the lognormal radius distribution of the particles were σn = 0.65 (1) nm and σv = 0.71 (1) nm. The particle concentration determined using this method was 3.0 (4) g l−1 or 4.2 (7) × 10−6 mol l−1. These results are affected slightly by the choice of data evaluation procedure, but not by the instruments: the participating laboratories at synchrotron SAXS beamlines, commercial and in-house-designed instruments were all able to provide highly consistent data. This demonstrates that SAXS is a suitable method for revealing particle size distributions in the sub-20 nm region (at minimum), out of reach for most other analytical methods. KW - SAXS KW - Small-angle X-ray scattering KW - Silver nanoparticles PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-422800 DO - https://doi.org/10.1107/S160057671701010X SN - 1600-5767 VL - 50 IS - 5 SP - 1280 EP - 1288 PB - (IUCr) International Union of Crystallography AN - OPUS4-42280 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liebig, F. A1 - Thünemann, Andreas A1 - Koetz, J. T1 - Ostwald Ripening Growth Mechanism of Gold Nanotriangles in Vesicular Template Phases N2 - The mechanism of nanotriangle formation in multivesicular vesicles (MMV) is investigated by using time-dependent SAXS measurements in combination with UV−vis spectroscopy, light, and transmission electron microscopy. In the first time period 6.5 nm sized spherical gold nanoparticles are formed inside of the vesicles, which build up soft nanoparticle aggregates. In situ SAXS experiments show a linear increase of the volume and molar mass of nanotriangles in the second time period. The volume growth rate of the triangles is 16.1 nm3/min, and the growth rate in the vertical direction is only 0.02 nm/min. Therefore, flat nanotriangles with a thickness of 7 nm and a diameter of 23 nm are formed. This process can be described by a diffusionlimited Ostwald ripening growth mechanism. TEM micrographs visualize soft coral-like structures with thin nanoplatelets at the periphery of the aggregates, which disaggregate in the third time period into nanotriangles and spherical particles. The 16 times faster growth of nanotriangles in the lateral than that in the vertical direction is related to the adsorption of symmetry breaking components, i.e., AOT and the polyampholyte PalPhBisCarb, on the {111} facets of the gold nanoplatelets in combination with confinement effects of the vesicular template phase. KW - Gold KW - Nanoparticle KW - Small-angle x-ray scattering KW - SAXS KW - Kinetics PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-379261 DO - https://doi.org/10.1021/acs.langmuir.6b02662 SN - 0743-7463 VL - 32 IS - 42 SP - 10928 EP - 10935 PB - American Chemical Society AN - OPUS4-37926 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szczerba, Wojciech A1 - Costo, R. A1 - Veintemillas-Verdaguer, S. A1 - del Puerto Morales, M. A1 - Thünemann, Andreas T1 - SAXS analysis of single- and multi-core iron oxide magnetic nanoparticles N2 - This article reports on the characterization of four superparamagnetic iron oxide nanoparticles stabilized with dimercaptosuccinic acid, which are suitable candidates for reference materials for magnetic properties. Particles p1 and p2 are single-core particles, while p3 and p4 are multi-core particles. Small-angle X-ray scattering analysis reveals a lognormal type of size distribution for the iron oxide cores of the particles. Their mean radii are 6.9 nm (p1), 10.6 nm (p2), 5.5 nm (p3) and 4.1 nm (p4), with narrow relative distribution widths of 0.08, 0.13, 0.08 and 0.12. The cores are arranged as a clustered network in the form of dense mass fractals with a fractal dimension of 2.9 in the multi-core particles p3 and p4, but the cores are well separated from each other by a protecting organic shell. The radii of gyration of the mass fractals are 48 and 44 nm, and each network contains 117 and 186 primary particles, respectively. The radius distributions of the primary particle were confirmed with transmission electron microscopy. All particles contain purely maghemite, as shown by X-ray absorption fine structure spectroscopy KW - Superparamagnetic nanoparticles KW - Iron oxide KW - Reference materials KW - SAXS KW - Small-angle x-ray scattering KW - XANES KW - X-ray absorption near-edge structure KW - X-ray absorption fine structure PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-395948 DO - https://doi.org/10.1107/S1600576717002370 SN - 1600-5767 VL - 50 IS - Part 2 SP - 481 EP - 488 PB - (IUCr) International Union of Crystallography AN - OPUS4-39594 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kästner, Claudia A1 - Lichtenstein, Dajana A1 - Lampen, Alfonso A1 - Thünemann, Andreas T1 - Monitoring the fate of small silver nanoparticles during artificial digestion N2 - The report on the results of an in vitro digestion study of silver nanoparticles in presence and absenceof food. The particles were poly(acrylic acid) stabilized ultra-small silver nanoparticles with a radius of 3.1 nm and a relative size distribution width of 0.2. As food components oil, starch, skimmed milk powderand a mixture thereof were chosen. Aggregation of the particles was quantified with small-angle X-rayscattering in terms of log-normal radii distributions. Complete aggregation of the primary particles wasdetermined in the absence of food. In contrast, the presence of oil and starch initiates a disaggregationin the intestine. Only small aggregates of 6 nm radii and aggregation numbers of 7 were found in thepresence of milk powder. It prevents primary particles from etching in the gastric and intestinal juice.Our results indicate that the silver nanoparticles can pass the digestion process in a nanoscale form butundergo a strong and food-dependent transformation in their state of aggregation. KW - Small-angle X-ray scattering KW - SAXS PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404099 DO - https://doi.org/10.1016/j.colsurfa.2016.08.013 SN - 0927-7757 SN - 1873-4359 VL - 526 SP - 76 EP - 81 PB - Elsevier B.V. AN - OPUS4-40409 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thünemann, Andreas A1 - Kurth, D.G. A1 - Beinhoff, M. A1 - Bienert, Ralf A1 - Schulz, Burkhard T1 - V-Shaped Crystalline Structures of Di-n-alkyl Esters of Phosphoric Acid N2 - We prepared crystals of di-n-alkyl esters of phosphoric acid with chain lengths of n = 10, 12, 14, 16, and 18. These were characterized by single-crystal X-ray analysis and differential scanning calorimetry (DSC). It was found that the alkyl chains are in an extended all-trans conformation and aligned close to perpendicular, forming V-shaped molecules. This is in strong contrast to the typical arrangement of the alkyl chains of phospholipids where the two alkyl chains are arranged parallel in the same direction (e.g., tuning fork configuration in bilayers). Additionally, it was found that the arrangement of the V-shaped molecules of the di-n-alkyl esters in neighboring stacks of the lamellar crystals is antiparallel for short chain lengths (n = 10 and 12) and parallel for the longer (n = 14 and 16). DSC reveals that the melting of the crystals increases systematically with increasing chain lengths from 48 to 82 C. The contribution of each methylene group to the melting enthalpy (70-133 kJ/mol) is independent of the chain length (3.9 kJ per mol CH2). PY - 2006 DO - https://doi.org/10.1021/la0603572 SN - 0743-7463 SN - 1520-5827 VL - 22 IS - 13 SP - 5856 EP - 5861 PB - American Chemical Society CY - Washington, DC AN - OPUS4-12446 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - DNA-like melting of adenine- and thymine-functionalized synthetic copolymers T2 - Polydays 2006, BAM CY - Berlin, Germany DA - 2006-10-04 PY - 2006 AN - OPUS4-12404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - (Functionalized) Nanoparticles T2 - Gemeinsames Institutskolloquium, Institut für Radiologie und Institut für Radiochemie FZ Rossendorf CY - Dresden, Germany DA - 2006-06-15 PY - 2006 AN - OPUS4-12491 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - The microfocus beamline at Berlin electron synchrotron (BESSY II): A new tool for the investigation of (polymeric) nanostructres T2 - Collaborative Research Centre SFB 625: From Single Molecules to Nanoscopically Structured Materials, University Mainz CY - Mainz, Germany DA - 2007-02-05 PY - 2007 AN - OPUS4-14661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Nanopartikel im Licht von BESSY II: Einblicke in ihre Struktur T2 - Jahrestagung der Gesellschaft deutscher Chemiker, Wissenschaftsforum Chemie CY - Ulm, Germany DA - 2007-09-16 PY - 2007 AN - OPUS4-14663 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Casse, O. A1 - Shkilnyy, A. A1 - Linders, J. A1 - Mayer, C. A1 - Häussinger, D. A1 - Völkel, A. A1 - Thünemann, Andreas A1 - Dimova, R. A1 - Cölfen, H. A1 - Meier, W. A1 - Schlaad, H. A1 - Taubert, A. T1 - Solution behavior of double-hydrophilic block copolymers in dilute aqueous solution N2 - The self-assembly of double-hydrophilic poly(ethylene oxide)–poly(2-methyl-2-oxazoline) diblock copolymers in water has been studied. Isothermal titration calorimetry, small-angle X-ray scattering, and analytical ultracentrifugation suggest that only single polymer chains are present in solution. In contrast, light scattering and transmission electron microscopy detect aggregates with radii of ca. 100 nm. Pulsed field gradient NMR spectroscopy confirms the presence of aggregates, although only 2% of the polymer chains undergo aggregation. Water uptake experiments indicate differences in the hydrophilicity of the two blocks, which is believed to be the origin of the unexpected aggregation behavior (in accordance with an earlier study by Ke et al. [Macromolecules2009, 42, 5339–5344]). The data therefore suggest that even in double-hydrophilic block copolymers, differences in hydrophilicity are sufficient to drive polymer aggregation, a phenomenon that has largely been overlooked or ignored so far. KW - Nanotechnology KW - Small-angle X-ray scatering KW - SAXS PY - 2012 DO - https://doi.org/10.1021/ma300621g SN - 0024-9297 SN - 1520-5835 VL - 45 IS - 11 SP - 4772 EP - 4777 PB - American Chemical Society CY - Washington, DC AN - OPUS4-26072 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nehring, R. A1 - Palivan, C.G. A1 - Moreno-Flores, S. A1 - Mantion, Alexandre A1 - Tanner, P. A1 - Toca-Herrera, J.L. A1 - Thünemann, Andreas A1 - Meier, W. T1 - Protein decorated membranes by specific molecular interactions N2 - Here we characterize new metal-functionalized amphiphilic diblock copolymers, developed for both surface and solution molecular recognition applications. Polybutadiene-block-poly(ethylene oxide) copolymers functionalized with nitrilotriacetic acid and tris(nitrilotriacetic acid) were complexed with nickel(II) to obtain coordination sites for oligohistidine residues of model proteins. Mixtures of functionalized polymers with the respective non-functionalized block copolymers self-assemble in aqueous solution into vesicular structures with a controlled density of the metal end-groups on their surface. In solution, binding of His6-tagged green fluorescent protein (EGFP) and red fluorescent protein (RFP) to the vesicle surface was quantified by fluorescence correlation spectroscopy. Small-angle X-ray scattering indicates an increase of the membrane thickness by 2-3 nm upon protein binding. Block copolymer monolayers at the air-water interface and on solid support served as a model system to characterize the protein-decorated membranes by Brewster angle microscopy and AFM. High resolution AFM of solid-supported, hydrated monolayers indicates that the proteins form densely packed and partially ordered arrays with the cylindrically shaped EGFP molecules lying flat on the surface of the films. KW - Amphiphilic copolymer KW - Metal centers KW - His-tag proteins KW - Molecular recognition PY - 2010 DO - https://doi.org/10.1039/c002838j SN - 1744-683X VL - 6 SP - 2815 EP - 2824 PB - RSC Publ. CY - Cambridge AN - OPUS4-21564 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scharf, Oliver A1 - Ihle, S. A1 - Ordavo, I. A1 - Arkadiev, V. A1 - Bjeoumikhov, A. A1 - Bjeoumikhova, S. A1 - Buzanich, Günter A1 - Gubzhokov, R. A1 - Günther, A. A1 - Hartmann, R. A1 - Kühbacher, M. A1 - Lang, M. A1 - Langhoff, N. A1 - Liebel, A. A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Soltau, H. A1 - Strüder, L. A1 - Thünemann, Andreas A1 - Wedell, R. T1 - Compact pnCCD-based X-ray camera with high spatial and energy resolution: a color X-ray camera N2 - For many applications there is a requirement for nondestructive analytical investigation of the elemental distribution in a sample. With the improvement of X-ray optics and spectroscopic X-ray imagers, full field X-ray fluorescence (FF-XRF) methods are feasible. A new device for high-resolution X-ray imaging, an energy and spatial resolving X-ray camera, is presented. The basic idea behind this so-called 'color X-ray camera' (CXC) is to combine an energy dispersive array detector for X-rays, in this case a pnCCD, with polycapillary optics. Imaging is achieved using multiframe recording of the energy and the point of impact of single photons. The camera was tested using a laboratory 30 µm microfocus X-ray tube and synchrotron radiation from BESSY II at the BAMline facility. These experiments demonstrate the suitability of the camera for X-ray fluorescence analytics. The camera simultaneously records 69696 spectra with an energy resolution of 152 eV for manganese Kα with a spatial resolution of 50 µm over an imaging area of 12.7 × 12.7 mm². It is sensitive to photons in the energy region between 3 and 40 keV, limited by a 50 µm beryllium window, and the sensitive thickness of 450 µm of the chip. Online preview of the sample is possible as the software updates the sums of the counts for certain energy channel ranges during the measurement and displays 2-D false-color maps as well as spectra of selected regions. The complete data cube of 264 × 264 spectra is saved for further qualitative and quantitative processing. KW - Color X-ray camera KW - X-ray fluorescence KW - pnCCD KW - Polycapillary optic KW - Synchrotron radiation PY - 2011 DO - https://doi.org/10.1021/ac102811p SN - 0003-2700 SN - 1520-6882 VL - 83 IS - 7 SP - 2532 EP - 2538 PB - American Chemical Society CY - Washington, DC AN - OPUS4-23948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Niehoff, A. A1 - Mantion, Alexandre A1 - McAloney, R. A1 - Huber, Alexandra A1 - Falkenhagen, Jana A1 - Goh, C.M. A1 - Thünemann, Andreas A1 - Winnik, M. A. A1 - Menzel, H. T1 - Elucidation of the structure of poly(gamma-benzyl-L-glutamate) nanofibers and gel networks in a helicogenic solvent N2 - The synthesis, characterization, self-assembly, and gel formation of poly(γ-benzyl-L-glutamate) (PBLG) in a molecular weight range from ca. 7,000–100,000 g/mol and with narrow molecular weight distribution are described. The PBLG is synthesized by the nickel-mediated ring-opening polymerization and is characterized by size-exclusion chromatography coupled with multiple-angle laser light scattering, NMR, and Fourier transform infrared spectroscopy. The self-assembly and thermoreversible gel formation in the helicogenic solvent toluene is investigated by transmission electron microscopy, atomic force microscopy, small-angle X-ray scattering, and synchrotron powder X-ray diffraction. At concentrations significantly below the minimum gelation concentration, spherical aggregates are observed. At higher concentrations, gels are formed, which show a 3D network structure composed of nanofibers. The proposed self-assembly mechanism is based on a distorted hexagonal packing of PBLG helices parallel to the axis of the nanofiber. The gel network forms due to branching and rejoining of bundles of PBLG nanofibers. The network exhibits uniform domains with a length of 200±42 nm composed of densely packed PBLG helices. KW - Poly(gamma-benzyl-L-glutamate) (PBLG) KW - Nickel-mediated NCA polymerization KW - Thermoreversible gel formation KW - Physical/supramolecular organogel KW - Nanofiber KW - Self-assembly KW - Alpha-helix KW - Nanotechnology KW - Small-angle X-ray scatering KW - SAXS PY - 2013 DO - https://doi.org/10.1007/s00396-012-2866-9 SN - 0303-402X SN - 1435-1536 VL - 291 IS - 6 SP - 1353 EP - 1363 PB - Springer CY - Berlin AN - OPUS4-28615 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - INSTANT technology for detection of nanoparticles T2 - Public workshop "Detection of Nanoparticles" at the Brandenburg University of Technology Cottbus-Senftenberg CY - Senftenberg, Germany DA - 2013-11-29 PY - 2013 AN - OPUS4-29674 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Metrology of Magnetic Iron Oxide Nanoparticles T2 - 16th International Conference on Small-Angle Scattering CY - Technical University Berlin (Berlin, Germany) DA - 2015-09-13 PY - 2015 AN - OPUS4-34350 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - How temperature determines structure of maghemite nanoparticles: A small-angle X-ray scattering study T2 - 10th International Conference on the Scientific and Clinical Applications of Magnetic Carriers CY - Dresden, Germany DA - 2014-06-10 PY - 2014 AN - OPUS4-31018 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -