TY - JOUR A1 - Löwa, N. A1 - Knappe, Patrick A1 - Wiekhorst, F. A1 - Eberbeck, D. A1 - Thünemann, Andreas A1 - Trahms, L. T1 - Hydrodynamic and magnetic fractionation of superparamagnetic nanoparticles for magnetic particle imaging N2 - Resovist® originally developed as a clinical liver contrast agent for Magnetic Resonance Imaging exhibits also an outstanding performance as a tracer in Magnetic Particle Imaging (MPI). In order to study the physical mechanism of the high MPI performance of Resovist®, we applied asymmetric flow field–flow fractionation (A4F) and static magnetic fractionation (SMF) to separate Resovist® into a set of fractions with defined size classes. As A4F based on an elution method separates MNP according to their hydrodynamic size, SMF fractionates a particle distribution by its magnetic moment. The obtained fractions of both separation techniques were then magnetically characterized by magnetorelaxometry measurements to extract the corresponding effective magnetic anisotropy and hydrodynamic size distribution parameters. Additionally, the MPI performance of each fraction was assessed using magnetic particle spectroscopy. With both separation techniques fractions (normalized to their iron amount) an MPI signal gain of a factor of two could be obtained, even though the distribution of effective anisotropy and hydrodynamic size were significantly different. Relating these findings to the results from magnetic characterization allows for a better understanding of the underlying mechanisms of MPI performance of Resovist®. This knowledge may help to improve the design of novel MPI tracers and development of separation methods. KW - Superparamagnetic nanoparticles KW - Asymmetric flow field–flow fractionation KW - Magnetic particle spectroscopy KW - Magnetorelaxometry KW - Magnetic separation KW - Magnetic particle imaging KW - Resovist® KW - Nanotechnology KW - SAXS KW - Nanoparticles PY - 2015 DO - https://doi.org/10.1016/j.jmmm.2014.08.057 SN - 0304-8853 VL - 380 SP - 266 EP - 270 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-32562 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rocha, S. A1 - Krastev, R. A1 - Thünemann, Andreas A1 - Carmo Pereira, M. A1 - Möhwald, H. A1 - Brezesinski, G. T1 - Adsorption of Amyloid beta-Peptide at Polymer Surfaces: A Neutron Reflectivity Study KW - Beta amyloid KW - Neutron reflectivity PY - 2005 SN - 1439-4235 SN - 1439-7641 IS - 6 SP - 2527 EP - 2534 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-11562 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Investigation of Nanostructures using Small-Angle X-Ray Scattering T2 - ICYS Special Seminar Nanotechnology (National Institute for Materials Science) CY - Tsukuba, Japan DA - 2014-03-26 PY - 2014 AN - OPUS4-30533 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Small-Angle X-Ray Scattering for Nanomedicine T2 - International Conference on Biological Barriers CY - Saarbrücken, Germany DA - 2014-02-16 PY - 2014 AN - OPUS4-30551 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 - CONF A1 - Saadeh, Qais A1 - Pauw, Brian Richard A1 - Thünemann, Andreas T1 - In-situ SAXS techniques N2 - This project studies the orientation of nanoparticles under the influence of external stimuli such as electric fields, magnetic fields and ultra-sonic vibrations. A set of functional sample holders that fit inside the sample chamber of a state-of-the-art Small Angle X-ray Scattering (SAXS) machine, called the “Multi-scale Analyzer for Ultrafine Structures” (MAUS). The MAUS has been custom engineered to serve as a miniaturized Synchrotron, thus enabling standard material to be characterized to a high standard. Our work is needed to detail the fine characterization of reference nano-particles, not only on the nano-scale, but also coupled with external agents. A second aim of this project is to verify a few proof-of-concept designs for the alignment of nano-particles. Where the alignment of nano-particles In-Situ is intended to further develop 3D printing technologies, and SAXS is an ideal choice to study the alignment of an oriented ensemble. For more information about the MAUS; https://www.bam.de/Content/DE/Pressemitteilungen/2018/AnalyticalSciences/2018-01-31-mit-maus-an-die-spitze-der-nano-forschung.html T2 - NanoWorkshop 2018 (Workshop on Reference Nanomaterials. Current situation and needs: development, measurement, standardization) CY - Berlin, Germany DA - 14.05.2018 KW - SAXS KW - Nano-particles alignment KW - Magnetic nano-particles PY - 2018 AN - OPUS4-44912 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pérez Blanes, H. A1 - Ghiasi, Pouria A1 - Sandkühler, J. A1 - Yesilcicek, Yasemin A1 - Pentzien, Simone A1 - Conradi, Andrea A1 - Prinz, Carsten A1 - Al-Sabbagh, Dominik A1 - Thünemann, Andreas A1 - Özcan Sandikcioglu, Özlem A1 - Witt, Julia T1 - High CO2 reduction activity on AlCrCoCuFeNi multi-principal element alloy nanoparticle electrocatalysts prepared by means of pulsed laser ablation N2 - Noble metal-free nanoparticles (NPs) based on multi-principal element alloys (MPEAs) were synthesized using a one-step pulsed laser ablation in liquids (PLALs) method for the electrochemical reduction of CO2. Laser ablation was performed in pure water or poly-(diallyldimethylammonium chloride) (PDADMAC)-containing an aqueous solution of Al8Cr17Co17Cu8Fe17Ni33 MPEA targets. Transmission electron microscopy (TEM) measurements combined with energy dispersive X-ray (EDX) mapping were used to characterize the structure and composition of the laser-generated MPEA nanoparticles (MPEA-NPs). These results confirmed the presence of a characteristic elemental distribution of a core-shell phase structure as the predominant NP species. The electrocatalytic performance of the laser-generated MPEA-NPs was characterized by linear sweep voltammetry (LSV) demonstrating an enhanced electrocatalytic CO2 activity for PDADMAC-stabilized NPs. The findings of these investigations indicate that MPEAs have great potential to replace conventional, expensive noble metal electrocatalysts. KW - Metals and Alloys KW - Surfaces KW - Biomaterials KW - Ceramics and Composites KW - Coatings and Films PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588218 DO - https://doi.org/10.1016/j.jmrt.2023.05.143 SN - 2238-7854 VL - 24 SP - 9434 EP - 9440 PB - Elsevier B.V. AN - OPUS4-58821 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pérez Blanes, H. A1 - Ghiasi, P. A1 - Sandkühler, J. A1 - Yesilcicek, Yasemin A1 - Pentzien, Simone A1 - Conradi, Andrea A1 - Prinz, Carsten A1 - Al-Sabbagh, Dominik A1 - Thünemann, Andreas A1 - Özcan Sandikcioglu, Özlem A1 - Witt, Julia T1 - High CO2 reduction activity on AlCrCoCuFeNi multi-principal element alloy nanoparticle electrocatalysts prepared by means of pulsed laser ablation N2 - Noble metal-free nanoparticles (NPs) based on multi-principal element alloys (MPEAs) were synthesized using a one-step pulsed laser ablation in liquids (PLALs) method for the electrochemical reduction of CO2. Laser ablation was performed in pure water or poly-(diallyldimethylammonium chloride) (PDADMAC)-containing an aqueous solution of Al8Cr17Co17Cu8Fe17Ni33 MPEA targets. Transmission electron microscopy (TEM) measurements combined with energy dispersive X-ray (EDX) mapping were used to characterize the structure and composition of the laser-generated MPEA nanoparticles (MPEA-NPs). These results confirmed the presence of a characteristic elemental distribution of a core-shell phase structure as the predominant NP species. The electrocatalytic performance of the laser-generated MPEA-NPs was characterized by linear sweep voltammetry (LSV) demonstrating an enhanced electrocatalytic CO2 activity for PDADMAC-stabilized NPs. The findings of these investigations indicate that MPEAs have great potential to replace conventional, expensive noble metal electrocatalysts. KW - Multi-principal element alloys KW - Chemically Complex Materials KW - CCMat KW - Electrocatalysis KW - Carbon dioxide reduction KW - Pulsed laser ablation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594018 DO - https://doi.org/10.1016/j.jmrt.2023.05.143 VL - 24 SP - 9434 EP - 9440 PB - Elsevier BV AN - OPUS4-59401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haase, A. A1 - Mantion, Alexandre A1 - Graf, P. A1 - Plendl, J. A1 - Thünemann, Andreas A1 - Meier, W. A1 - Taubert, A. A1 - Luch, A. T1 - A novel type of silver nanoparticles and their advantages in toxicity testing in cell culture systems N2 - Silver nanoparticles (SNPs) are among the most commercialized nanoparticles worldwide. Often SNP are used because of their antibacterial properties. Besides that they possess unique optic and catalytic features, making them highly interesting for the creation of novel and advanced functional materials. Despite its widespread use only little data exist in terms of possible adverse effects of SNP on human health. Conventional synthesis routes usually yield products of varying quality and property. It thus may become puzzling to compare biological data from different studies due to the great variety in sizes, coatings or shapes of the particles applied. Here, we applied a novel synthesis approach to obtain SNP of well-defined colloidal and structural properties. Being stabilized by a covalently linked small peptide, these particles are nicely homogenous, with narrow size distribution, and form monodisperse suspensions in aqueous solutions. We applied these peptide-coated SNP in two different sizes of 20 or 40 nm (Ag20Pep and Ag40Pep) and analyzed responses of THP-1-derived human macrophages while being exposed against these particles. Gold nanoparticles of similar size and coating (Au20Pep) were used for comparison. The cytotoxicity of particles was assessed by WST-1 and LDH assays, and the uptake into the cells was confirmed via transmission electron microscopy. In summary, our data demonstrate that this novel type of SNP is well suited to serve as model system for nanoparticles to be tested in toxicological studies in vitro. KW - Silver nanoparticles KW - Peptide coating KW - Nanotoxicity PY - 2012 DO - https://doi.org/10.1007/s00204-012-0836-0 SN - 0340-5761 SN - 1432-0738 VL - 86 IS - 7 SP - 1089 EP - 1098 PB - Springer CY - Berlin ; Heidelberg [u.a.] AN - OPUS4-26269 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shovo, Redoy Gazi A1 - Thünemann, Andreas A1 - Katcharava, Zviadi A1 - Marinvo, Anja A1 - Hoppe, Richard A1 - Woltersdorf, Georg A1 - Du, Mengxue A1 - Androsch, Rene A1 - de Souza e Silva, Juliana Martins A1 - Busse, Karste A1 - Binder, Wolfgang H. T1 - Generating Tagged Micro- and Nanoparticles of Poly(ethylene furanoate) and Poly(ethylene terephthalate) as Reference Materials N2 - Detecting nanoplastic particles in environmental samples and biological tissues remains a significant challenge, especially in view of newly emerging polymers, not yet commercially exploited. Fluorescent labeling provides a tagging strategy to overcome this limitation by reducing the detection limit of individual particles, especially for small-sized particles. We present a method for producing labeled nanoparticles (NP/MP) of poly(ethylene terephthalate) (PET) and poly(ethylene furanoate) (PEF), tagged with Alexa Fluor 633 or Alexa Fluor 647. Our preparations used mechanical grinding or solvent-based approaches (confined impinging jet mixing, ((CIJ, precipitation), generating particles with hydrodynamic diameters of 200–700 nm, displaying long-term stability in water of up to 57 days. Stable suspensions with concentrations of the particles ranging from 10 µg/mL (surfactant-free, by solvent mixing) to 5.88 mg/mL (precipitation, containing surfactant) were generated with zeta-potentials from −5 to −50 mV. Characterization of the nanoparticles by SEC, DSC, and XRD showed no significant changes in molecular weight, thermal behavior, or crystallinity via the solvent-based methods, compared to the pristine polymer, highlighting their suitability for producing standardized nanoparticle dispersions. Fluorescence spectroscopy of the Alexa-dye-labeled particles confirmed the successful incorporation of the Alexa dyes, so improving monitoring of their biological profiles of the PEF-MP/NPs. s-SNOM (near field imaging) could identify individual PEF-particles sized ∼200 nm by direct imaging. KW - Reference Materials KW - Nanoplastics KW - Microplastics KW - Polymer KW - Fluorescence PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655531 DO - https://doi.org/10.1002/marc.202500839 SN - 1521-3927 VL - 47 IS - 4 SP - 1 EP - 11 PB - Wiley VHC-Verlag CY - Weinheim AN - OPUS4-65553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abram, Sarah-Luise A1 - Mrkwitschka, Paul A1 - Thünemann, Andreas A1 - Radnik, Jörg A1 - Häusler, I. A1 - Bresch, Harald A1 - Hodoroaba, Vasile-Dan A1 - Resch-Genger, Ute T1 - Iron Oxide Nanocubes as a New Certified Reference Material for Nanoparticle Size Measurements N2 - The rational design and increasing industrial use of nanomaterials require a reliable characterization of their physicochemical key properties like size, size distribution, shape, and surface chemistry. This calls for nanoscale reference materials (nanoRMs) for the validation and standardization of commonly used characterization methods closely matching real-world nonspherical nano-objects. This encouraged us to develop a nonspherical nanoRM of very small size consisting of 8 nm iron oxide nanocubes (BAM-N012) to complement spherical gold, silica, and polymer nanoRMs. In the following, the development and production of this nanoRM are highlighted including the characterization by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) as complementary methods for size and shape parameters, homogeneity and stability studies, and calculation of a complete uncertainty budget of the size features. The determination of the nanocubes’ edge length by TEM and SAXS allows a method comparison. In addition, SAXS measurements can also provide the mean particle number density and the mass concentration. The certified size parameters, area equivalent circular diameter and square edge length, determined by TEM with a relative expanded uncertainty below 9%, are metrologically traceable to a natural constant for length, the very precisely known (111) lattice spacing of silicon. Cubic BAM-N012 qualifies as a certified nanoRM for estimating the precision and trueness, validation, and quality assurance of particle size and shape measurements with electron microscopy and SAXS as well as other sizing methods suitable for nanomaterials. The production of this new iron oxide nanocube RM presents an important achievement for the nanomaterial community, nanomaterial manufacturers, and regulators. KW - Certification KW - SAXS KW - Homogeneity KW - Nano KW - Particle KW - Iron oxide KW - Quality assurance KW - Reference material KW - Size KW - Electron microscopy KW - Stability KW - Shape PY - 2023 DO - https://doi.org/10.1021/acs.analchem.3c00749 SN - 0003-2700 VL - 95 IS - 33 SP - 12223 EP - 12231 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-58176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mrkwitschka, Paul A1 - Abram, Sarah-Luise A1 - Thünemann, Andreas A1 - Rühle, Bastian A1 - Radnik, Jörg A1 - Bresch, Harald A1 - Resch-Genger, Ute A1 - Hodoroaba, Vasile-Dan T1 - The Role of Electron Microscopy in the Development of Monodisperse Cubic Iron Oxide Nanoparticles as Certified Reference Material for Size and Shape N2 - BAM is currently building up a platform of novel nanoRMs relying on iron oxide nanoparticles of different shape, size and surface chemistry. Iron oxide was chosen as a core material because of its relevance to the material and life sciences. As a first candidate of this series, we present cubic iron oxide nanoparticles with a nominal edge length of 8 nm. These particles were synthesized by thermal decomposition of iron oleate in high boiling organic solvents adapting well-known literature procedures. After dilution to a concentration suitable for electron microscopy (TEM and SEM) as well as for small-angle X-ray scattering (SAXS) measurements, the candidate nanoRM was bottled and assessed for homogeneity and stability by both methods following the guidelines of ISO 17034 and ISO Guide 35. The particle sizes obtained by both STEM-in-SEM and TEM are in excellent agreement with a minimum Feret of 8.3 nm ± 0.7 nm. The aspect ratio (AR) of the iron oxide cubes were extracted from the images as the ratio of minimum Feret to Feret resulting in an AR of 1.18 for TEM to 1.25 for SEM. Alternatively, a rectangular bounding box was fitted originating from the minimum Feret and the longest distance through the particle in perpendicular direction. This led to AR values of 1.05 for TEM and 1.12 for SEM, respectively. The results confirm the almost ideal cubic shape. KW - Reference nanoparticles KW - Iron oxide KW - Cubical shape KW - Electron microscopy KW - SAXS KW - Nano CRM KW - Size PY - 2022 DO - https://doi.org/10.1017/S1431927622003610 SN - 1435-8115 VL - 28 IS - Suppl. 1 SP - 802 EP - 805 PB - Cambridge University Press AN - OPUS4-55599 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Pauw, Brian Richard A1 - Smith, A. J. A1 - Snow, T. A1 - Shebanova, O. A1 - Sutter, J. P. A1 - Ilavsky, J. A1 - Hermida-Merino, D. A1 - Smales, Glen Jacob A1 - Terrill, N. J. A1 - Thünemann, Andreas A1 - Bras, W. T1 - Extending SAXS instrument ranges through addition of a portable, inexpensive USAXS module N2 - Ultra-SAXS can enhance the capabilities of existing SAXS/WAXS beamlines and laboratory instruments. A compact Ultra-SAXS module has been developed, which extends the measurable q-range with 0:0015 < q 1/nm) < 0:2, allowing structural dimensions between 30 < D(nm) < 4000 to be probed in addition to the range covered by a high-end SAXS/WAXS instrument. By shifting the module components in and out on their respective motor stages, SAXS/WAXS measurements can be easily and rapidly interleaved with USAXS measurements. KW - Small-angle scattering PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504867 DO - https://doi.org/10.48550/arXiv.1904.00080 SN - 2331-8422 SP - 1 EP - 25 PB - Cornell University CY - Ithaca, NY AN - OPUS4-50486 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kröcke, N. A1 - Grebenteuch, S. A1 - Keil, C. A1 - Demtröder, S. A1 - Koch, L. A1 - Thünemann, Andreas A1 - Benning, R. A1 - Haase, H. T1 - Effect of different drying methods on nutrient quality of the yellow mealworm (Tenebrio molitor L.) N2 - Yellow mealworm (Tenebrio molitor L.) represents a sustainable source of proteins and fatty acids for feed and food. Industrial production of mealworms necessitates optimized processing techniques, where drying as the first postharvest procedure is of utmost importance for the quality of the final product. This study examines the nutritional quality of mealworm larvae processed by rack oven drying, vacuum drying or freeze drying, respectively. Proximate composition and fatty acid profile were comparable between the dried larvae. In contrast, larvae color impressions and volatile compound profiles were very much dependent on processing procedure. High-temperature rack oven drying caused pronounced darkening with rather low content of volatiles, pointing toward the progress of Maillard reaction. On the other hand, vacuum drying or freeze drying led to enrichment of volatile Maillard reaction and lipid oxidation intermediates, whose actual sensory relevance needs to be clarified in the future. Beyond sensory and visual importance drying intermediates have to be considered with regard to their metal ion chelating ability; in particular for essential trace elements such as Zn2+. This study found comparable total zinc contents for the differently dried mealworm samples. However, dried larvae, in particular after rack oven drying, had only low zinc accessibility, which was between 20% and 40%. Therefore, bioaccessibility rather than total zinc has to be considered when their contribution to meeting the nutritional requirements for zinc in humans and animals is evaluated. KW - Food PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476320 DO - https://doi.org/10.3390/insects10040084 SN - 2075-4450 VL - 10 IS - 4 SP - 84, 1 EP - 13 PB - MDPI AN - OPUS4-47632 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Saloga, Patrick E. J. A1 - Thünemann, Andreas T1 - Microwave-Assisted Synthesis of Ultrasmall Zinc Oxide Nanoparticles N2 - We report on ultrasmall zinc oxide single-crystalline nanoparticles of narrow size distribution and long-term colloidal stability. These oleate-stabilized nanoparticles were synthesized using microwave-assisted synthesis for 5 min, corresponding to a 99% decrease in synthesis time, when compared to the conventional synthesis method. It was observed that the average particle radius increases from 2.6 ± 0.1 to 3.8 ± 0.1 nm upon increasing synthesis temperature from 125 to 200 °C. This change also corresponded to observed changes in the optical band gap and the fluorescence energy of the particles, from 3.44 ± 0.01 to 3.36 ± 0.01 eV and from 2.20 ± 0.01 to 2.04 ± 0.01 eV, respectively. Small-angle X-ray scattering, dynamic light scattering, and UV–vis and fluorescence spectroscopy were employed for particle characterization. Debye–Scherrer analysis of the X-ray diffraction (XRD) pattern reveals a linear increase of the crystallite size with synthesis temperature. The consideration of the convolution of a Lorentz function with a Gaussian function for data correction of the instrumental peak broadening has a considerable influence on the values for the crystallite size. Williamson–Hall XRD analyses in the form of the uniform deformation model, uniform stress deformation model, and uniform deformation energy density model revealed a substantial increase of strain, stress, and deformation energy density of the crystallites with decreasing size. Exponential and power law models were utilized for quantification of strain, stress, and deformation energy density. KW - SAXS KW - Zinc oxide KW - Microwave synthesis KW - Nanoparticles PY - 2019 DO - https://doi.org/10.1021/acs.langmuir.9b01921 SN - 0743-7463 VL - 35 IS - 38 SP - 12469 EP - 12482 PB - American Chemical Society CY - Washington, D.C., USA AN - OPUS4-49136 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - A look inside nanoparticles N2 - Small-angle scattering is the method of choice when it comes to obtaining information about the interior of nanoparticles. The aim is to make nanotechnology safer. While the use of small-angle neutron scattering (SANS) is limited to a few instruments in the world, small-angle X-ray scattering (SAXS) is widely accessible, with an upward trend. The example of core-shell particles shows how simple their analysis is with data from an Anton Paar laboratory system. Here, SAXS is a central tool for the development of new reference materials based on poly(methyl) acrylate-PVDF core-shell particles. The dimensions of the cores and shells can be precisely determined. A detailed analysis makes it possible to show that the cores contain fluorinated and nonfluorinated polymers, whereas the shell consist only of PVDF. This core-shell particles with a diameter around 40 nm show a significantly higher PVDF beta phase content than the PVDF homopolymer when using an emulsion polymerization technique. This finding is of importance with respect to applications in electroactive devices. T2 - SAXS excites: International SAXS Symposium 2019 CY - Graz, Austria DA - 24.09.2019 KW - Small-angle X-ray scattering KW - SAXS KW - Nanoplastics PY - 2019 AN - OPUS4-49126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brandl, F. A1 - Lederle, F. A1 - Härter, C. A1 - Thünemann, Andreas A1 - Beuermann, S. T1 - From gaseous vinylidene fluoride to electroactive poly(vinylidene fluoride) – Inducing β-phase by formation of block copolymers and composite materials N2 - Polymeric core-shell particles were synthesized in a semi-batch emulsion polymerization process. The shell of the particles consist of PVDF with a high amount of beta-phase. Small-angle X-ray scattering (SAXS) was used to quantify the size of the cores of the particles and the thickness of the shell. T2 - Macromolecular Colloquium Freiburg CY - Freiburg, Germany DA - 20.02.2019 KW - Small-angle x-ray scattering KW - SAXS KW - Nanoparticle KW - Polymer PY - 2019 AN - OPUS4-47467 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - The Single Chain Architecture of (Bio)Polymers in Contact with Nanoplastics N2 - In contrast to microplastics, little is known about nanoplastics (1 to 100 nm). In order to make the dectecability of nanoplasics more reliable, we started to develop nanoplastic reference materials. This project also aims to anser the question of how the single chain conformation of bio(polymers) changes in contact with nanoplastics. Small-angle X-ray and neutron scattering methods are suitable methods for studing this topic. Recently the soft and hard interactions between polystyrene nanoplasics and human serum albumin corona was investigated with small-angle neutron scattering. Here we concentrate on small-angle X-ray scattering as our favorite method to study how (bio)polymers change their conformation in contact with nanoplastics. The scattering of bovine serum albumin in its native state can be detected easily. The scattering pattern of this biopolymer changes dramatically when its globular stucture changes to a coil structure. Modeling of chain conformations and the calculation of the scattering pattern is relatively easy to perform. Numerous model calculations will be provided to predict the changes of conformation of single bio(polymer) chains when in conatact with nanoplastics. These predictions will be compared with recent experimenal results from in situ measurments of bio(polymers) in contact with nanoplastics. The impact of temperature, polymer concentration and salt on the single-chain conformation changes will be discussed. T2 - PolyDays 2019 CY - Berlin, Germany DA - 11.09.2019 KW - Small-angle X-ray scattering KW - SAXS KW - Nanoparticle KW - Protein KW - Nanoplastics PY - 2019 AN - OPUS4-48959 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 -