TY - JOUR A1 - Saloga, Patrick E. J. A1 - Rybak, Tina A1 - Thünemann, Andreas T1 - Microwave-Assisted Synthesis of ZnO Nanoparticles: Phase Transfer to Water N2 - Herein, a simple one-pot procedure is reported to obtain aqueous zinc oxide (ZnO) nanoparticle dispersions from ZnO nanoparticles dispersed in cyclohexane. In the process, polyoxyethylene (20) sorbitan monooleate (polysorbate 80, Tween 80) functions as a phase transfer agent and colloidal stabilizer. The particles grow in a defined manner during the transfer, presumably via coalescence. The final particle radii are tuneable in the range from 2.3 ± 0.1 nm to 5.7 ± 0.1 nm depending on the incubation time of the dispersion at 90 °C. Small-angle X-ray scattering is employed to determine the particle radius distributions before and after phase transfer. The larger ZnO particle radii are associated with a redshift of the optical bandgap and luminescence emission, as expected for semiconductor nanoparticles. The particles presented here exhibit a relative size distribution width of 20%, rendering them attractive for applications in, e.g., biology or catalysis. The latter application is demonstrated at the photocatalytic degradation of methylene blue dye. KW - SAXS KW - Small-angle X-ray scattering KW - nanoparticle PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-551502 VL - 24 IS - 6 SP - 1 EP - 7 PB - Wiley AN - OPUS4-55150 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chowdhary, S. A1 - Schmidt, R. F. A1 - Sahoo, A. K. A1 - tom Dieck, T. A1 - Hohmann, T. A1 - Schade, B. A1 - Brademann-Jock, Kerstin A1 - Thünemann, Andreas A1 - Netz, R. R. A1 - Gradzielski, M. A1 - Koksch, B. T1 - Rational design of amphiphilic fluorinated peptides: evaluation of self-assembly properties and hydrogel formation N2 - Advanced peptide-based nanomaterials composed of self-assembling peptides (SAPs) are of emerging interest in pharmaceutical and biomedical applications. The introduction of fluorine into peptides, in fact, offers unique opportunities to tune their biophysical properties and intermolecular interactions. In particular, the degree of fluorination plays a crucial role in peptide engineering as it can be used to control the characteristics of fluorine-specific interactions and, thus, peptide conformation and self-assembly. Here, we designed and explored a series of amphipathic peptides by incorporating the fluorinated amino acids (2S)-4-monofluoroethylglycine (MfeGly), (2S)-4,4-difluoroethylglycine (DfeGly) and (2S)-4,4,4-trifluoroethylglycine (TfeGly) as hydrophobic components. This approach enabled studying the impact of fluorination on secondary structure formation and peptide self-assembly on a systematic basis. We show that the interplay between polarity and hydrophobicity, both induced differentially by varying degrees of side chain fluorination, does affect peptide folding significantly. A greater degree of fluorination promotes peptide fibrillation and subsequent formation of physical hydrogels in physiological conditions. Molecular simulations revealed the key role played by electrostatically driven intra-chain and inter-chain contact pairs that are modulated by side chain fluorination and give insights into the different self-organization behaviour of selected peptides. Our study provides a systematic report about the distinct features of fluorinated oligomeric peptides with potential applications as peptide-based biomaterials. KW - Small-angle X-ray scattering KW - SAXS KW - Amyloid PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-553504 SN - 2040-3364 VL - 14 IS - 28 SP - 10176 EP - 10189 PB - Royal Society of Chemistry AN - OPUS4-55350 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Paul, M. B. A1 - Fahrenson, C. A1 - Givelet, L. A1 - Herrmann, T. A1 - Loescher, K. A1 - Böhmert, L. A1 - Thünemann, Andreas A1 - Braeuning, A. A1 - Sieg, H. T1 - Beyond microplastics ‑ investigation on health impacts of submicron and nanoplastic particles after oral uptake in vitro N2 - The continuously increasing use of plastics is supposed to result in a rising exposure of MNPs to humans. Available data on human health risks of microplastics after oral uptake increased immensely in the past years and indicates very likely only low risks after oral consumption. Concerning nanoplastics, uptake, transport and potential adverse effects after oral uptake are less well understood. This study aims to investigate differences between microplastic particles and particles in the submicron- and nanoscaled size derived from food-relevant polymers with a particle size range consistent with higher potential for cellular uptake, fate, and effects when applied to human intestinal and liver cells. This work includes the development of cellular and subcellular detection methods for synthetic polymeric particles in the micro- and nanometer-range, using Scanning Electron Microscopy, Small-Angle X-ray and Dynamic Light Scattering methods, Asymmetric Flow Field Flow Fractionation, octanol-water fractionation, fluorescence microscopy and flow cytometry. Polylactic acid (250 nm and 2 μm (polydisperse)), melamine formaldehyde (366 nm) and polymethylmethacrylate (25 nm) were thoroughly characterized. The submicro- and nanoplastic test particles showed an increased uptake and transport quantity through intestinal cells. Both types of particles resulted in observed differences of uptake behavior, most likely influenced by different lipophilicity, which varied between the polymeric test materials. Toxic effects were detected after 24 h only in overload situations for the particles in the submicrometer range. This study provides further evidence for gastrointestinal uptake of submicro- and nanoplastics and points towards differences regarding bioavailability between microplastics and smaller plastic particles that may result following the ingestion of contaminated food and beverages. Furthermore, the results reinforce the importance for studying nanoplastics of different materials of varying size, surface properties, polymer composition and hydrophobicity. KW - Small-angle X-ray scattering KW - SAXS KW - nanoparticle PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-550741 VL - 2 SP - 1 EP - 19 PB - Springer Nature AN - OPUS4-55074 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chambers, M. S. A1 - Hunter, R. D. A1 - Hollamby, M. J. A1 - Pauw, Brian Richard A1 - Smith, A. J. A1 - Snow, T. A1 - Danks, A. E. A1 - Schnepp, Z. T1 - In Situ and Ex Situ X‑ray Diffraction and Small-Angle X‑ray Scattering Investigations of the Sol−Gel Synthesis of Fe3N and Fe3C N2 - Iron nitride (Fe3N) and iron carbide (Fe3C) nanoparticles can be prepared via sol−gel synthesis. While sol−gel methods are simple, it can be difficult to control the crystalline composition, i.e., to achieve a Rietveld-pure product. In a previous in situ synchrotron study of the sol−gel synthesis of Fe3N/Fe3C, we showed that the reaction proceeds as follows: Fe3O4 → FeOx → Fe3N → Fe3C. There was considerable overlap between the different phases, but we were unable to ascertain whether this was due to the experimental setup (side-on heating of a quartz capillary which could lead to thermal gradients) or whether individual particle reactions proceed at different rates. In this paper, we use in situ wide- and small-angle X-ray scattering (wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS)) to demonstrate that the overlapping phases are indeed due to variable reaction rates. While the initial oxide nanoparticles have a small range of diameters, the size range expands considerably and very rapidly during the oxide−nitride transition. This has implications for the isolation of Rietveld-pure Fe3N, and in an extensive laboratory study, we were indeed unable to isolate phasepure Fe3N. However, we made the surprising discovery that Rietveld-pure Fe3C nanoparticles can be produced at 500 °C with a sufficient furnace dwell time. This is considerably lower than the previous reports of the sol−gel synthesis of Fe3C nanoparticles. KW - Small-angle X-ray Scattering KW - SAXS KW - Diffraction KW - XRD KW - Scattering KW - Sol-gel KW - Iron nitride KW - Nanoparticles KW - Iron carbide KW - Catalyst KW - In-situ KW - Ex-situ KW - Synthesis KW - Synchrotron PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-548226 VL - 61 IS - 18 SP - 6742 EP - 6749 PB - ACS Publications CY - Washington AN - OPUS4-54822 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kohlbrecher, J. A1 - Breßler, Ingo T1 - Updates in SASfit for fitting analytical expressions and numerical models to small-angle scattering patterns N2 - Small-angle scattering is an increasingly common method for characterizing particle ensembles in a wide variety of sample types and for diverse areas of application. SASfit has been one of the most comprehensive and flexible curve-fitting programs for decades, with many specialized tools for various fields. Here, a selection of enhancements and additions to the SASfit program are presented that may be of great benefit to interested and advanced users alike: (a) further development of the technical basis of the program, such as new numerical algorithms currently in use, a continuous integration practice for automated building and packaging of the software, and upgrades on the plug-in system for easier adoption by third-party developers; (b) a selection of new form factors for anisotropic scattering patterns and updates to existing form factors to account for multiple scattering effects; (c) a new type of a very flexible distribution called metalog [Keelin (2016). Decis. Anal. 13, 243–277], and regularization techniques such as the expectation-maximization method [Dempster et al. (1977). J. R. Stat. Soc. Ser. B (Methodological), 39, 1–22; Richardson (1972) J. Opt. Soc. Am. 62, 55; Lucy (1974). Astron. J. 79, 745; Lucy (1994). Astron. Astrophys. 289, 983–994], which is compared with fits of analytical size distributions via the non-linear least-squares method; and (d) new structure factors, especially for ordered nano- and meso-scaled material systems, as well as the Ornstein–Zernike solver for numerical determination of particle interactions and the resulting structure factor when no analytical solution is available, with the aim of incorporating its effects into the small-angle scattering intensity model used for fitting with SASfit. KW - Small-angle scattering KW - Numerical models KW - Structure factors KW - Regularization KW - SAXS KW - SANS PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-565069 SN - 0021-8898 SN - 1600-5767 VL - 55 IS - 6 SP - 1677 EP - 1688 PB - Wiley-Blackwell CY - Oxford AN - OPUS4-56506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zou, T. A1 - Nonappa, N. A1 - Khavani, M. A1 - Vuorte, M. A1 - Penttilä, P. A1 - Zitting, A. A1 - Valle-Delgado, J. J. A1 - Elert, Anna Maria A1 - Silbernagl, Dorothee A1 - Balakshin, M. A1 - Sammalkorpi, M. A1 - Österberg, M. T1 - Experimental and Simulation Study of the Solvent Effects on the Intrinsic Properties of Spherical Lignin Nanoparticles N2 - Spherical lignin nanoparticles (LNPs) fabricated via nanoprecipitation of dissolved lignin are among the most attractive biomass-derived nanomaterials. Despite various studies exploring the methods to improve the uniformity of LNPs or seeking more application opportunities for LNPs, little attention has been given to the fundamental aspects of the solvent effects on the intrinsic properties of LNPs. In this study, we employed a variety of experimental techniques and molecular dynamics (MD) simulations to investigate the solvent effects on the intrinsic properties of LNPs. The LNPs were prepared from softwood Kraft lignin (SKL) using the binary solvents of aqueous acetone or aqueous tetrahydrofuran (THF) via nanoprecipitation. The internal morphology, porosity, and mechanical properties of the LNPs were analyzed with electron tomography (ET), small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), and intermodulation AFM (ImAFM). We found that aqueous acetone resulted in smaller LNPs with higher uniformity compared to aqueous THF, mainly ascribing to stronger solvent−lignin interactions as suggested by MD simulation results and confirmed with aqueous 1,4-dioxane (DXN) and aqueous dimethyl sulfoxide (DMSO). More importantly, we report that both LNPs were compact particles with relatively homogeneous density distribution and very low porosity in the internal structure. The stiffness of the particles was independent of the size, and the Young’s modulus was in the range of 0.3−4 GPa. Overall, the fundamental understandings of LNPs gained in this study are essential for the design of LNPs with optimal performance in applications. KW - Lignin KW - Electron tomography KW - Intermodulation AFM KW - Modulus KW - SAXS PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-546948 SN - 1520-5207 VL - 125 IS - 44 SP - 12315 EP - 12328 PB - ACS AN - OPUS4-54694 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wolf, J. A1 - Stawski, Tomasz A1 - Smales, Glen Jacob A1 - Thünemann, Andreas A1 - Emmerling, Franziska T1 - Towards automation of the polyol process for the synthesis of silver nanoparticles N2 - Metal nanoparticles have a substantial impact across diferent felds of science, such as photochemistry, energy conversion, and medicine. Among the commonly used nanoparticles, silver nanoparticles are of special interest due to their antibacterial properties and applications in sensing and catalysis. However, many of the methods used to synthesize silver nanoparticles often do not result in well-defned products, the main obstacles being high polydispersity or a lack of particle size tunability. We describe an automated approach to on-demand synthesis of adjustable particles with mean radii of 3 and 5 nm using the polyol route. The polyol process is a promising route for silver nanoparticles e.g., to be used as reference materials. We characterised the as-synthesized nanoparticles using small-angle X-ray scattering, dynamic light scattering and further methods, showing that automated synthesis can yield colloids with reproducible and tuneable properties. KW - Sillver KW - Nanoparticles KW - Automated synthesis KW - Chemputer KW - Scattering KW - SAXS PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-546803 VL - 12 IS - 1 SP - 1 EP - 9 PB - Nature Springer AN - OPUS4-54680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Crouzier, L. A1 - Feltin, N. A1 - Delvallée, A. A1 - Pellegrino, Francesco A1 - Maurino, V. A1 - Cios, Grzegorz A1 - Tokarski, T. A1 - Salzmann, Christoph A1 - Deumer, J. A1 - Gollwitzer, C. A1 - Hodoroaba, Vasile-Dan T1 - Correlative analysis of the dimensional properties of bipyramidal titania nanoparticles by complementing electron microscopy with other methods N2 - In this paper, the accurate determination of the size and size distribution of bipyramidal anatase nanoparticles (NPs) after deposition as single particles on a silicon substrate by correlative Scanning Electron Microscopy (SEM) with Atomic Force Microscopy (AFM) analysis is described as a new measurement procedure for metrological purposes. The knowledge of the exact orientation of the NPs is a crucial step in extracting the real 3D dimensions of the particles. Two approaches are proposed to determine the geometrical orientation of individual nano‐bipyramides: (i) AFM profiling along the long bipyramid axis and (ii) stage tilting followed by SEM imaging. Furthermore, a recently developed method, Transmission Kikuchi Diffraction (TKD), which needs preparation of the crystalline NPs on electron‐transparent substrates such as TEM grids, has been tested with respect to its capability of identifying the geometrical orientation of the individual NPs. With the NPs prepared homogeneously on a TEM grid, the transmission mode in a SEM, i.e., STEM‐in‐SEM (or T‐SEM), can be also applied to extract accurate projection dimensions of the nanoparticles from the same sample area as that analysed by SEM, TKD and possibly AFM. Finally, Small Angle X‐ray Scattering (SAXS) can be used as an ensemble technique able to measure the NPs in liquid suspension and, with ab‐initio knowledge of the NP shape from the descriptive imaging techniques, to provide traceable NP size distribution and particle concentration. KW - Nanoparticles KW - Complex-shape KW - Bipyramid KW - Electron microscopy KW - AFM KW - Size measurements KW - TKD KW - STEM-in-SEM KW - SAXS KW - Nanoparticle concentration KW - Correlative analysis PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-539888 SN - 2079-4991 VL - 11 IS - 12 SP - 1 EP - 19 PB - MDPI CY - Basel AN - OPUS4-53988 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Navarro, L. A1 - Thünemann, Andreas A1 - Klinger, D. T1 - Solvent Annealing of Striped Ellipsoidal Block Copolymer Particles: Reversible Control over Lamellae Asymmetry, Aspect Ratio, and Particle Surface N2 - Solvent annealing is a versatile tool to adjust the shape and morphology of block copolymer (BCP) particles. During this process, polar solvents are often used for block-selective swelling. However, such water-miscible solvents can induce (partial) solubilization of one block in the surrounding aqueous medium, thus, causing complex structural variations and even particle disassembly. To reduce the complexity in morphology control, we focused on toluene as a nonpolar polystyrene-selective solvent for the annealing of striped polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) ellipsoids. The selective stretching of PS chains produces unique asymmetric lamellae structures, which translate to an increase in the particle aspect ratio after toluene evaporation. Complete reversibility is achieved by changing to chloroform as a nonselective solvent. Moreover, surfactants can be used to tune block-selective wetting of the particle surface during the annealing; for example, a PS shell can protect the internal lamellae structure from disassembly. Overall, this versatile postassembly process enables the tailoring of the structural features of striped colloidal ellipsoids by only using commercial BCPs and solvents. KW - Small-angle X-ray scattering KW - SAXS KW - Nanoparticle KW - Polymer PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-543731 VL - 11 IS - 3 SP - 319 EP - 335 PB - American Chemical Society AN - OPUS4-54373 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sieg, H. A1 - Klusmann, L. A1 - Ellermann, A. L. A1 - Böhmert, L. A1 - Thünemann, Andreas A1 - Braeuning, A. T1 - Counterions determine uptake and effects of aluminum in human intestinal and liver cells N2 - Aluminum (Al) is highly abundant in the biosphere and can occur in different physico-chemical states. It is present in human food and undergoes transitions between dissolved and particulate species during the passage of the gastrointestinal tract. Moreover, in a complex matrix such as food different inorganic and organic counterions can affect the chemical behavior of Al following oral uptake. In this work, the effects of different counterions, namely chloride, citrate, sulfate, lactate and acetylacetonate, on Al uptake and toxicity in the human intestine are studied. The respective Al salts showed different dissolution behavior in biological media and formed nanoscaled particles correlating in reverse with the amount of their dissolved fraction. The passage through the intestinal barrier was studied using a Caco-2 Transwell® system, showing counterion-dependent variance in cellular uptake and transport. In addition, Al toxicity was investigated using Al species (Al3+, metallic Al0 and oxidic γAl2O3 nanoparticles) and counterions individually or in mixtures on Caco-2 and HepG2 cells. The strongest toxicity was observed using a combination of Al species, depending on solubility, and the lipophilic counterion acetylacetonate. Notably, only the combination of both led to toxicity, while both substances individually did not show toxic effects. A toxification of previously non-toxic Al-species by the presence of acetylacetonate is shown here for the first time. The dependency on the concentration of free Al ions was demonstrated using sodium hydrogen phosphate, which was able to counteract the toxic effects by complexing free Al ions. These findings, using Al salts as an example for a common food contaminant, underline the importance of a consideration of the chemical properties of human nutrition, especially dissolution and hydrophobicity, which can significantly influence the cellular uptake and effects of xenobiotic substances. KW - SAXS KW - Small-angle X-ray scattering KW - Nanoparticle PY - 2022 U6 - https://doi.org/10.1016/j.tiv.2021.105295 VL - 79 SP - 1 EP - 7 PB - Elsevier AN - OPUS4-54110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -