TY - JOUR A1 - Said Shabaan Omara, Shereen A1 - Rehim, M.H.A. A1 - Ghoneim, A. A1 - Madkour, Sherif Aly Hassan Aly A1 - Thünemann, Andreas A1 - Turky, G. A1 - Schönhals, Andreas T1 - Structure-property relationships of hyperbranched polymer/kaolinite nanocomposites N2 - Two methods were employed to prepare hyperbranched polyamine ester (HPAE)/kaolinite (Ka) nanocomposites resulting in different morphologies. In the case of the in situ polymerization, diethanolamine is inserted as monomer between the Ka layers and polymerized with methyl acrylate to prepare HPAE/Ka–DEA nanocomposites. For the ex situ method, Ka is modified with dodecylamine and solution-blended with HPAE. The former method leads to an intercalated morphology where the latter approach results in an exfoliated structure, as proofed by SAXS and TEM. A complementary combination of methods like differential scanning calorimetry (DSC), broadband dielectric relaxation (BDS), and specific heat spectroscopy (SHS) was used to investigate both kinds of nanocomposites in detail. Above Tg, the dielectric spectra are dominated by the conductivity contribution while the segmental dynamics is retrieved by SHS. A comparison of the temperature dependencies reveals a decoupling of segmental dynamics and conductivity, which becomes weaker with decreasing fragility. PY - 2015 DO - https://doi.org/10.1021/acs.macromol.5b01693 SN - 0024-9297 SN - 1520-5835 VL - 48 IS - 18 SP - 6562 EP - 6573 PB - American Chemical Society CY - Washington, DC AN - OPUS4-34424 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Omara, Shereen Shabaan A1 - Turky, G. A1 - Ghoneim, A. A1 - Thünemann, Andreas A1 - Abdel Rehim, M. H. A1 - Schönhals, Andreas T1 - Hyperbranched poly(amidoamine)/kaolinite nanocomposites: Structure and charge carrier dynamics N2 - An ex-situ approach was applied to prepare nanocomposites from hyperbranched poly(amidoamine) and modified kaolinite (Ka-DCA). The structure of the polymer and the corresponding nanocomposites was investigated by FTIR, DSC, SAXS and TEM. SAXS might suggest a partly exfoliated structure of the nanocomposites, which was supported by TEM. The molecular dynamics was studied by means of broadband dielectric spectroscopy (BDS). The dielectric spectra are dominated by a conductivity contribution at higher temperatures for all samples investigated. The obtained results further indicated that DC conductivity is increased by 4 orders of magnitude with increasing concentration of Ka-DCA nanofiller. Further, a significant separation between the conductivity relaxation time and that of segmental dynamics was observed. The decoupling phenomenon and the conductivity mechanism were discussed in detail. This study provides insights about the influence of the nanofiller on the structure and the conductivity contribution of nanocomposites of hyperbranched polymers including the decoupling phenomenon and fragility. KW - Hyperbranched polymers KW - Nanocomposites KW - Conductivity PY - 2017 DO - https://doi.org/10.1016/j.polymer.2017.06.017 SN - 0032-3861 VL - 121 SP - 64 EP - 74 PB - Elsevier Ltd. AN - OPUS4-40648 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lange, Alyna A1 - Holtzheimer, Lea A1 - Clarke, Coby A1 - Thünemann, Andreas A1 - Taubert, Andreas T1 - Complex Self-Organization in n-Alkylammonium Sulfobetaine Zwitterions with High Thermal Stabilities and High Expansion Coefficients N2 - Sulfobetaine zwitterions made from n-alkyl dimethylamines and butanesultone yield a series of n-alkylammonium sulfobetaine zwitterions with complex self-organization behavior. The compounds are thermally quite stable and the length of the alkyl chain directly affects all phase transition temperatures of the compounds: the longer the alkyl chain, the higher the transition temperature. All compounds exhibit lamellar order and the different phases are characterized by a lower temperature orthorhombic and a higher temperature hexagonal in-plane order. The phase transition from the orthorhombic to the hexagonal phase is always associated with an increase of the long period. The phase transition is also associated with a rather high thermal expansion coefficient. KW - SAXS KW - Small-angle X-ray scattering KW - Nanostructure PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626276 DO - https://doi.org/10.1021/acs.langmuir.4c02892 SN - 1520-5827 VL - 41 SP - 4422 EP - 4434 PB - American Chemical Society (ACS) AN - OPUS4-62627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hildebrandt, Jana A1 - Taubert, Andreas A1 - Thünemann, Andreas T1 - Synthesis and Characterization of Ultra‐Small Gold Nanoparticles in the Ionic Liquid 1‐Ethyl‐3‐methylimidazolium Dicyanamide, [Emim][DCA] N2 - AbstractWe report on gold clusters with around 62 gold atoms and a diameter of 1.15±0.10 nm. Dispersions of the clusters are long‐term stable for two years at ambient conditions. The synthesis was performed by mixing tetrachloroauric acid (HAuCl4 ⋅ 3 H2O) with the ionic liquid 1‐ethyl‐3‐methylimidazolium dicyanamide ([Emim][DCA]) at temperatures of 20 to 80 °C. Characterization was performed with small‐angle X‐ray scattering (SAXS), UV‐Vis spectroscopy, and MALDI‐TOF mass spectrometry. A three‐stage model is proposed for the formation of the clusters, in which cluster growth from gold nuclei takes place according to the Lifshitz‐Slyozov‐Wagner (LSW) model followed by oriented attachment to form colloidal stable clusters. KW - Reference materials KW - SAXS KW - Gold KW - Nanoparticle KW - Small-angle X-ray scattering KW - Ionic liquid PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588203 DO - https://doi.org/10.1002/open.202300106 SN - 2191-1363 VL - 44 SP - 1 EP - 19 PB - Wiley AN - OPUS4-58820 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Purohit, Purv A1 - Huacuja Sánchez, Jesús A1 - Wang, D.-Y. A1 - Emmerling, Franziska A1 - Thünemann, Andreas A1 - Heinrich, G. A1 - Schönhals, Andreas T1 - Structure - property relationships of nanocomposites based on polypropylene and layered double hydroxides N2 - Nanocomposites based on polypropylene (PP) and organically modified ZnAl layered double hydroxides (ZnAl-LDH) were prepared by melt blending and investigated by a combination of differential scanning calorimetry (DSC), small- and wide-angle X-ray scattering (SAXS and WAXS), and dielectric relaxation spectroscopy (DRS). An average number of stack size of LDH layers is calculated by analyzing the SAXS data which is close to that of pure organically modified ZnAl-LDH. Scanning microfocus SAXS investigations show that the ZnAl-LDH is homogeneously distributed in the PP matrix as stacks of 4–5 layers with an intercalated morphology. DSC and WAXS results show that the degree of crystallinity decreases linearly with the increasing content of LDH. The extrapolation of this dependence to zero estimates a limiting concentration of ca. 40% LDH where the crystallization of PP is completely suppressed by the nanofiller. The dielectric spectra of the nanocomposites show several relaxation processes which are discussed in detail. The intensity of the dynamic glass transition (β-relaxation) increases with the concentration of LDH. This is attributed to the increasing concentration of the exchanged anion dodecylbenzenesulfonate (SDBS) which is adsorbed at the LDH layers. Therefore, a detailed analysis of the β-relaxation provides information about the structure and the molecular dynamics in the interfacial region between the LDH layers and the polypropylene matrix which is otherwise dielectrically invisible (low dipole moment). As a main result, it is found that the glass transition temperature in this interfacial region is by 30 K lower than that of pure polypropylene. This is accompanied by a drastic change of the fragility parameter deduced from the relaxation map. KW - Nanocomposites KW - Layered double hydroxide KW - Dielectric spectroscopy KW - X-ray scattering KW - Polypropylene PY - 2011 DO - https://doi.org/10.1021/ma200323k SN - 0024-9297 SN - 1520-5835 VL - 44 IS - 11 SP - 4342 EP - 4354 PB - American Chemical Society CY - Washington, DC AN - OPUS4-23921 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Purohit, Purv A1 - Wang, D.-Y. A1 - Emmerling, Franziska A1 - Thünemann, Andreas A1 - Heinrich, G. A1 - Schönhals, Andreas T1 - Arrangement of layered double hydroxide in a polyethylene matrix studied by a combination of complementary methods N2 - Organically modified ZnAl Layered Double Hydroxides (ZnAl-LDH) was synthesized and melt blended with polyethylene to obtain nanocomposites. The resulting morphology was investigated by a combination of Differential Scanning Calorimetry (DSC), Small and Wide-angle X-ray scattering (SAXS and WAXS) and dielectric relaxation spectroscopy (DRS). The arrangement (intercalation) of polyethylene chains between LDH stacks was investigated employing SAXS. The homogeneity of the nanocomposites and average number of stack size (4–6 layers) were determined using scanning microfocus SAXS (BESSY II). DSC and WAXS results show that the degree of crystallinity decreases linearly with the increasing content of LDH. The extrapolation of this dependence to zero estimates a limiting concentration of ca. 45% LDH where the crystallization of PE is completely suppressed by the nanofiller. The dielectric spectra of the nanocomposites show several relaxation processes which are discussed in detail. The intensity of the dynamic glass transition (β-relaxation) increases with the concentration of LDH. This is attributed to the increasing concentration of the exchanged anion sodium dodecylbenzene sulfonate (SDBS) which is adsorbed at the LDH layers. Therefore, a detailed analysis of the β-relaxation provides information about the structure and the molecular dynamics in the interfacial region between the LDH layers and the polyethylene matrix which is otherwise dielectrically invisible (low dipole moment). KW - Dielectric spectroscopy KW - Polyethylene nanocomposites KW - Layered double hydroxides PY - 2012 DO - https://doi.org/10.1016/j.polymer.2012.03.041 SN - 0032-3861 SN - 1873-2291 VL - 53 IS - 11 SP - 2245 EP - 2254 PB - Springer CY - Berlin AN - OPUS4-25810 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leng, Jing A1 - Purohit, Purv A1 - Kang, N. A1 - Wang, D.-Y. A1 - Falkenhagen, Jana A1 - Emmerling, Franziska A1 - Thünemann, Andreas A1 - Schönhals, Andreas T1 - Structure-property relationships of nanocomposites based on polylactide and MgAl layered double hydroxides N2 - Nanocomposites based on poly(ʟ-lactide) (PLA) and organically modified MgAl Layered Double Hydroxides (MgAl-LDH) were prepared by melt blending and investigated by a combination of Differential Scanning Calorimetry (DSC), Small- and Wide-Angle X-ray Scattering (SAXS, WAXS), and dielectric spectroscopy (BDS). Scanning microfocus SAXS investigations show that the MgAl-LDH is homogeneously distributed in the matrix as stacks of 6 layers and/or partly exfoliated layers. DSC and WAXS show that the degree of crystallinity decreases linearly with the content of LDH. The extrapolation of the dependencies (DSC and WAXS) to zero estimates a limiting concentration of LDH CCri of ca. 21 wt% where the crystallization of PLA is completely suppressed by the nanofiller. The dielectric behavior of neat PLA show two relaxation regions, a β-relaxation at low temperatures related to localized fluctuations and the α-relaxation at higher temperatures due to the dynamic glass transition. The dielectric spectra of the nanocomposites show several additional relaxation processes compared to neat PLA which are discussed in detail. For the nanocomposites around 260 K (ƒ = 1 kHz) an additional process is observed which intensity increases with increasing concentration of LDH. This process is mainly attributed to the exchanged dodecylbenzene sulfonate (SDBS) molecules which are adsorbed at the LDH layers and form a mixed phase with the polymer close to the layers and stacks. An analysis of this process provides information about the molecular dynamics in the interfacial region between the LDH layers and the PLA matrix which reveal glassy dynamics in this region. In the temperature range around 310 K (ƒ = 1 kHz) a further process is observed. Its relaxation rate has an unusual saddle-like temperature dependence. It was assigned to rotational fluctuations of water molecules in a nanoporous environment provided by the LDH filler. Above the glass transition temperature a further process is observed at temperatures above. It is related to Maxwell/Wagner/Sillars polarization due to the blocking of charges at the nanofiller. KW - Polymer based nanocomposites KW - Polylactide KW - Layered double hydroxides KW - Dielectric spectroscopy PY - 2015 DO - https://doi.org/10.1016/j.eurpolymj.2015.05.008 SN - 0014-3057 SN - 1873-1945 VL - 68 SP - 338 EP - 354 PB - Elsevier CY - Oxford AN - OPUS4-33257 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leng, Jing A1 - Kang, Nianjun A1 - Wang, De-Yi A1 - Falkenhagen, Jana A1 - Thünemann, Andreas A1 - Schönhals, Andreas T1 - Structure–Property Relationships of Nanocomposites Based on Polylactide and Layered Double Hydroxides – Comparison of MgAl and NiAl LDH as Nanofiller N2 - Nanocomposites based on poly(L-lactide) (PLA) and organically modified Ni/Al layered double hydroxides (NiAl/LDHs) are prepared by melt blending and investigated by a combination of size exclusion chromatography, differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), wide-angle X-ray scattering, and broadband dielectric spectroscopy. A detailed comparison to the behavior of the corresponding MgAl/LDH–PLA nanocomposites is made. SAXS investigations show that the morphology of the NiAl/LDH–PLA nanocomposites is more intercalated compared to the MgAl/LDH based PLA nanocomposite, which is more exfoliated. The DSC investigation gives a different dependence of the degree of crystallization on the concentration of LDH for NiAl/LDH–PLA than for MgAl/LDH–PLA nanocomposite system. These differences are discussed taking the differences of the morphologies of both systems into account. Broadband dielectric spectroscopy reveals information about the molecular dynamics where essential differences are observed for all relaxation processes taking place in both systems which were related to the different morphologies. KW - Nanocomposites KW - Polylactide PY - 2017 DO - https://doi.org/10.1002/macp.201700232 SN - 1022-1352 SN - 1521-3935 VL - 218 IS - 20 SP - Article 1700232, 1 EP - 12 PB - Wiley-VCH Verlag AN - OPUS4-42597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Iannuzzi, Maurizio A1 - Chowdhary, Suvrat A1 - Fiedler, Holly A1 - Haoues, Kilian A1 - Schade, Boris A1 - Thünemann, Andreas A1 - Quaas, Elisa A1 - Koksch, Beate T1 - Rational design of polyfluorinated peptide-based materials: Self-assembly of an amphiphilic motif N2 - Generation of a pH sensitive amphiphilic block oligopeptide containing the bioactive function RGD and a library of derivatives varying the length of the hydrophobic core and the degree of side chain fluorination. Peptide rational design enables us to obtain desired features (pH sensitivity etc.). The introduction of fluorine alters a wide range of peptide properties such as secondary structure propensity, folding, thermal and metabolic stability and proteolytic resistance. The RGD function is highly effective at promoting the attachment of numerous cell types to a plethora of materials. This small sequence is the principal integrin-binding domain present within ECM proteins such as fiobronectin, vibronectin and fibrinogen. For this reason, RGD containing peptides offer several advantages for biomaterials applications. The use of RGD compared with native ECM proteins, minimized the risk of immune reactivity or pathogen transfer. Herein in this work, we present the peptide motif X6RGD and its fluoro-derivates for prospective receptor-specific drug delivery in cancer theraphy. Overall, our results demonstrate that high degree of fluorination achieved triggers a selective modification of peptide self-assembly dramatically improving the structural properties, the carrier suitability, enzimatic degradation profiles and cytotoxic features of the fluoropeptide conjugate(s). T2 - 37th European Peptide Symposium CY - Florence, Italy DA - 25.08.2024 KW - Nanostructure KW - SAXS KW - Small-angle X-ray scattering PY - 2024 SN - 1099-1387 VL - 30 IS - S2 SP - 247 EP - 248 PB - Wiley CY - New York, NY AN - OPUS4-62191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Voss, L. A1 - Hsiao, I-L. A1 - Ebisch, Maximilian A1 - Vidmar, J. A1 - Dreiack, N. A1 - Böhmert, L. A1 - Stock, V. A1 - Braeuning, A. A1 - Loeschner, K. A1 - Laux, P. A1 - Thünemann, Andreas A1 - Lampen, A. A1 - Sieg, H. T1 - The presence of iron oxide nanoparticles in the food pigment E172 N2 - Iron oxides used as food colorants are listed in the European Union with the number E172. However, there are no specifications concerning the fraction of nanoparticles in these pigments. Here, seven E172 products were thoroughly characterized. Samples of all colors were analyzed with a Broad spectrum of methods to assess their physico-chemical properties. Small-Angle X-ray Scattering (SAXS), Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), zeta-potential, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), X-ray diffraction (XRD), Brunauer-Emmett-Teller analysis (BET), Asymmetric Flow Field-Flow Fractionation (AF4) and in vitro cell viability measurements were used. Nanoparticles were detected in all E172 samples by TEM or SAXS measurements. Quantitative results from both methods were comparable. Five pigments were evaluated by TEM, of which four had a size median below 100 nm, while SAXS showed a size median below 100 nm for six evaluated pigments. Therefore, consumers May be exposed to iron oxide nanoparticles through the consumption of food pigments. KW - SAXS KW - Small-angle X-ray scattering KW - Nanoparticle PY - 2020 DO - https://doi.org/10.1016/j.foodchem.2020.127000 VL - 327 SP - 127000 PB - Elsevier Ltd. AN - OPUS4-50810 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haase, A. A1 - Rott, S. A1 - Mantion, Alexandre A1 - Graf, P. A1 - Plendl, J. A1 - Thünemann, Andreas A1 - Meier, W.P. A1 - Taubert, A. A1 - Luch, A. A1 - Reiser, G T1 - Effects of silver nanoparticles on primary mixed neural cell cultures: uptake, oxidative stress and acute calcium responses N2 - In the body, nanoparticles can be systemically distributed and then may affect secondary target organs, such as the central nervous system (CNS). Putative adverse effects on the CNS are rarely investigated to date. Here, we used a mixed primary cell model consisting mainly of neurons and astrocytes and a minor proportion of oligodendrocytes to analyze the effects of well-characterized 20 and 40 nm silver nanoparticles (SNP). Similar gold nanoparticles served as control and proved inert for all endpoints tested. SNP induced a strong size-dependent cytotoxicity. Additionally, in the low concentration range (up to 10 µg/ml of SNP), the further differentiated cultures were more sensitive to SNP treatment. For detailed studies, we used low/medium dose concentrations (up to 20 µg/ml) and found strong oxidative stress responses. Reactive oxygen species (ROS) were detected along with the formation of protein carbonyls and the induction of heme oxygenase-1. We observed an acute calcium response, which clearly preceded oxidative stress responses. ROS formation was reduced by antioxidants, whereas the calcium response could not be alleviated by antioxidants. Finally, we looked into the responses of neurons and astrocytes separately. Astrocytes were much more vulnerable to SNP treatment compared with neurons. Consistently, SNP were mainly taken up by astrocytes and not by neurons. Immunofluorescence studies of mixed cell cultures indicated stronger effects on astrocyte morphology. Altogether, we can demonstrate strong effects of SNP associated with calcium dysregulation and ROS formation in primary neural cells, which were detectable already at moderate dosages. KW - Silver nanoparticles KW - Neurons KW - Oxidative stress KW - Protein carbonyls KW - Calcium KW - Reference material KW - Nanoparticle KW - Small-angle X-ray scattering KW - SAXS PY - 2012 DO - https://doi.org/10.1093/toxsci/kfs003 SN - 1096-6080 SN - 1096-0929 VL - 126 IS - 2 SP - 457 EP - 468 PB - Oxford University Press CY - Oxford AN - OPUS4-25633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Graf, P. A1 - Mantion, Alexandre A1 - Haase, A. A1 - Thünemann, Andreas A1 - Masic, A. A1 - Luch, A. A1 - Taubert, A. T1 - Silicification of peptide-coated chiral nanosilver: Novel core-shell structures N2 - Nanosilver is increasingly used in optics, medicine and analytical chemistry. We recently reported on the synthesis and properties of novel peptide-coated chiral nanosilver [1] using a small hexapeptide based on the amino acids CKK. In a continuation of our previous work, we use the peptides to catalyse TEOS hydrolysis in order to form a dense silica layer shell around a single nanoparticle, preventing chemical etching, allowing their inclusion in other inorganics, and making them biocompatible. Because of mild reaction conditions, the peptide integrity is ensured, as the chiral information which is contained in the nanoparticle. Moreover, these novel core-shell structures remain well-dispersed and are biocompatible. The possibility of further processing (creation of metamaterials etc.) is also in the focus of our interest. KW - Hybrid materials KW - Nanosilver KW - Core shell PY - 2010 DO - https://doi.org/10.1002/zaac.201009133 SN - 0044-2313 SN - 1521-3749 SN - 0372-7874 SN - 0863-1786 SN - 0863-1778 VL - 636 IS - 11 SP - 2115 PB - Wiley-VCH CY - Weinheim AN - OPUS4-22409 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Noskov, Sergey A1 - Scherer, Christian A1 - Maskos, Michael A1 - Thünemann, Andreas T1 - Determination of Hamaker constants of polymeric nanoparticles in organic solvents by asymmetrical flow field-flow fractionation N2 - Interaction forces between all objects are either of repulsive or attractive nature. Concerning attractive interactions, the determination of dispersion forces are of special interest since they appear in all colloidal systems and have a crucial influence on the properties and processes in these systems. One possibility to link theory and experiment is the description of the London–Van der Waals forces in terms of the Hamaker constant, which leads to the challenging problem of calculating the van der Waals interaction energies between colloidal particles. Hence, the determination of a Hamaker constant for a given material is needed when interfacial phenomena such as adhesion are discussed in terms of the total potential energy between particles and substrates. In this work, the asymmetrical flow field-flow fractionation (AF-FFF) in combination with a Newton algorithm based iteration process was used for the determination of Hamaker constants of different nanoparticles in toluene. KW - Hamaker constant KW - Asymmetrical flow field flow fractionation KW - Lifshitz KW - Van der Waals KW - London KW - Thermodynamic KW - Interaction PY - 2013 DO - https://doi.org/10.1016/j.chroma.2012.12.001 SN - 0021-9673 VL - 1274 SP - 151 EP - 158 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-27625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Voss, L. A1 - Saloga, Patrick E. J. A1 - Stock, V. A1 - Böhmert, L. A1 - Braeuning, A. A1 - Thünemann, Andreas A1 - Lampen, A. A1 - Sieg, H. T1 - Correction to "Environmental impact of ZnO nanoparticles evaluated by in vitro simulated digestion" N2 - This is a corrigendum to the original article "Environmental impact of ZnO nanoparticles evaluated by in vitro simulated digestion" that was published in the journal "ACS Applied Nano Materials", vol. 3 (2020), no. 1, pp. 724-733. PY - 2020 DO - https://doi.org/10.1021/acsanm.0c01054 VL - 3 IS - 5 SP - 4914 EP - 4914 PB - American Chemical Society CY - Washington, D.C., USA AN - OPUS4-50812 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Renz, F. A1 - Jung, S. A1 - Klein, M. A1 - Menzel, Michael A1 - Thünemann, Andreas T1 - Molecular switching complexes with iron and tin as central atom N2 - The precursor [FeIII(L)Cl] (LH1.5) and several reactive groups for surface anchoring, full surface shielding can be reached, which leads to reduced protein adsorption of albumin and fibrinogen. In addition, adherent thrombocytes were not activated. This could be clearly shown by immunostaining adherent proteins and analyzing the thrombocyte covered area. The presented work provides an important strategy for the development of application relevant hemocompatible 3D structured materials. KW - Nanotechnology KW - thrombocyte adhesion KW - biomedical applications PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-308196 DO - https://doi.org/10.1039/c4tb00184b SN - 2050-750X SN - 2050-7518 VL - 2 IS - 23 SP - 3626 EP - 3635 PB - Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-30819 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kästner, Claudia A1 - Thünemann, Andreas T1 - Catalytic reduction of 4-nitrophenol using silver nanoparticles with adjustable activity 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. With PAA as stabilizer, the catalytic activity of 436 ± 24 L g⁻¹ s⁻¹ is the highest reported in literature for silver nanoparticles. GSH and BSA passivate the surface substantially resulting in a catalytic activity of 77.6 ± 0.9 and 3.47 ± 0.50 L g⁻¹ s⁻¹, respectively. KW - Silver nanoparticles KW - Catalysis KW - Reference material KW - Protein coating PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370655 DO - https://doi.org/10.1021/acs.langmuir.6b01477 SN - 0743-7463 SN - 1520-5827 VL - 32 IS - 29 SP - 7383 EP - 7391 AN - OPUS4-37065 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szczerba, Wojciech A1 - Schott, M. A1 - Riesemeier, Heinrich A1 - Thünemann, Andreas A1 - Kurth, D.G. T1 - Thermally induced structural rearrangement of the Fe(II) coordination geometry in metallo-supramolecular polyelectrolytes N2 - Rigid rod-type metallo-supramolecular coordination polyelectrolytes with Fe(II) centres (Fe-MEPEs) are produced via the self-assembly of the ditopic ligand 1,4-bis(2,2':6',2''-terpyridine-4'-yl)benzene (tpy-ph-tpy) and Fe(II) acetate. Fe-MEPEs exhibit remarkable electrochromic properties; they change colour from blue to transparent when an electric potential is applied. This electrochemical process is generally reversible. The blue colour in the ground state is a result of a metal-to-ligand charge transfer at the Fe(II) centre ion in a quasi-octahedral geometry. When annealed at temperatures above 100 °C, the blue colour turns into green and the formerly reversible electrochromic properties are lost, even after cooling down to room temperature. The thermally induced changes in the Fe(II) coordination sphere are investigated in situ during annealing of a solid Fe-MEPE using X-ray absorption fine structure (XAFS) spectroscopy. The study reveals that the thermally induced transition is not accompanied by a redox process at the Fe(II) centre. From the detailed analysis of the XAFS spectra, the changes are attributed to structural changes in the coordination sphere of the Fe(II) site. In the low temperature state, the Fe(II) ion rests in a quasi-octahedral coordination environment surrounded by six nitrogen atoms of the pyridine rings. The axial Fe–N bond length is 1.94 Å, while the equatorial bond length amounts to 1.98 Å. In the high temperature state, the FeN6-site exhibits a distortion with the axial Fe–N bonds being shortened to 1.88 Å and the equatorial Fe–N bonds being elongated to 2.01 Å. KW - Metallo-supramolecular polyelectrolytes KW - Electrochromism KW - XANES KW - EXAFS KW - Local structure KW - Thermal stability PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317331 DO - https://doi.org/10.1039/c4cp01187b SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 36 SP - 19694 EP - 19701 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-31733 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chowdhary, S. A1 - Moschner, J. A1 - Mikolajczak, D. J. A1 - Becker, M. A1 - Thünemann, Andreas A1 - Kästner, Claudia A1 - Klemczak, D. A1 - Stegemann, A.-K. A1 - Böttcher, C. A1 - Metrangolo, P. A1 - Netz, R. R. A1 - Koksch, B. T1 - The Impact of Halogenated Phenylalanine Derivatives on NFGAIL Amyloid Formation N2 - The hexapeptide hIAPP22–27 (NFGAIL) is known as a crucial amyloid core sequence of the human islet amyloid polypeptide (hIAPP) whose aggregates can be used to better understand the wild‐type hIAPP′s toxicity to β‐cell death. In amyloid research, the role of hydrophobic and aromatic‐aromatic interactions as potential driving forces during the aggregation process is controversially discussed not only in case of NFGAIL, but also for amyloidogenic peptides in general. We have used halogenation of the aromatic residue as a strategy to modulate hydrophobic and aromatic‐aromatic interactions and prepared a library of NFGAIL variants containing fluorinated and iodinated phenylalanine analogues. We used thioflavin T staining, transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS) to study the impact of side‐chain halogenation on NFGAIL amyloid formation kinetics. Our data revealed a synergy between aggregation behavior and hydrophobicity of the phenylalanine residue. This study introduces systematic fluorination as a toolbox to further investigate the nature of the amyloid self‐assembly process. KW - Small-angle X-ray scattering KW - SAXS KW - Nanoparticle KW - Nanostructure KW - Peptide KW - Amyloid PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518632 DO - https://doi.org/10.1002/cbic.202000373 VL - 21 IS - 24 SP - 3544 EP - 3554 PB - Wiley CY - Weinheim AN - OPUS4-51863 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brandl, F. A1 - Thünemann, Andreas A1 - Beuermann, S. T1 - Poly(meth)acrylate-PVDF core–shell particles from emulsion polymerization: preferential formation of the PVDF β crystal phase N2 - A facile and convenient approach for the synthesis of core–shell particles via emulsion polymerization is presented. The shell consists of poly(vinylidene fluoride) (PVDF) and the core of poly(methyl methacrylate) (PMMA), poly(glycidyl methacrylate) (PGMA) or poly(methyl acrylate) (PMA). In a first step, a non-fluorinated (meth)acrylate monomer is polymerized in the emulsion to produce poly(meth)acrylate core particles. Secondly, vinylidene fluoride (VDF) is directly added to the reactor and polymerized for shell formation. Small-angle X-ray scattering (SAXS) was employed to characterize the structure of the core–shell particles. Interestingly, the particles’ core contains fluorinated and non-fluorinated polymers, whereas the shell of the particles consists only of PVDF. The resulting particles with a diameter of around 40 nm show a significantly higher PVDF β phase content than the PVDF homopolymer obtained by emulsion polymerization KW - Small-angle x-ray scattering KW - SAXS KW - Nanopatricle KW - Polymer PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465910 DO - https://doi.org/10.1039/C8PY01236A SN - 1759-9954 SN - 1759-9962 VL - 9 IS - 44 SP - 5359 EP - 5369 PB - The Royal Society of Chemistry AN - OPUS4-46591 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liebig, F. A1 - Sarhan, R. M. A1 - Schmitt, C. N. Z. A1 - Thünemann, Andreas A1 - Prietzel, C. A1 - Bargheer, M. A1 - Koetz, J. T1 - Gold Nanotriangles with Crumble Topping and their Influence on Catalysis and Surface‐Enhanced Raman Spectroscopy N2 - By adding hyaluronic acid (HA) to dioctyl sodium sulfosuccinate (AOT)‐stabilized gold nanotriangles (AuNTs) with an average thickness of 7.5±1 nm and an edge length of about 175±17 nm, the AOT bilayer is replaced by a polymeric HA‐layer leading to biocompatible nanoplatelets. The subsequent reduction process of tetrachloroauric acid in the HA‐shell surrounding the AuNTs leads to the formation of spherical gold nanoparticles on the platelet surface. With increasing tetrachloroauric acid concentration, the decoration with gold nanoparticles can be tuned. SAXS measurements reveal an increase of the platelet thickness up to around 14.5 nm, twice the initial value of bare AuNTs. HRTEM micrographs show welding phenomena between densely packed particles on the platelet surface, leading to a crumble formation while preserving the original crystal structure. Crumbles crystallized on top of the platelets enhance the Raman signal by a factor of around 20, and intensify the plasmon‐driven dimerization of 4‐nitrothiophenol (4‐NTP) to 4,4′‐dimercaptoazobenzene in a yield of up to 50 %. The resulting crumbled nanotriangles, with a biopolymer shell and the absorption maximum in the second window for in vivo imaging, are promising candidates for biomedical sensing. KW - SAXS KW - Small-angle X-ray scattering KW - Nanoparticle KW - Gold PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503977 DO - https://doi.org/10.1002/cplu.201900745 VL - 85 IS - 3 SP - 519 EP - 526 PB - Wiley-VCH Verlag CY - Weinheim AN - OPUS4-50397 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kästner, Claudia A1 - Böhmert, Linda A1 - Braeuning, Albert A1 - Lampen, Alfonso A1 - Thünemann, Andreas T1 - Fate of fluorescence labels - Their adsorption and desorption kinetics to silver nanoparticles N2 - Silver nanoparticles are among the most widely used and produced nanoparticles. Because of their frequent application in consumer products, the assessment of their toxicological potential has seen a renewed importance. A Major difficulty is the traceability of nanoparticles in in vitro and in vivo experiments. Even if the particles are labeled, for example, by a fluorescent marker, the dynamic exchange of ligands often prohibits their spatial localization. Our study provides an insight into the adsorption and desorption kinetics of two different fluorescent labels on silver nanoparticles with a core radius of 3 nm by dynamic light scattering, small-angle X-ray scattering, and fluorescence spectroscopy. We used BSA-FITC and tyrosine as examples for common fluorescent ligands. It is shown that the adsorption of BSA-FITC takes at least 3 days, whereas tyrosine adsorbs immediately. The quantitative amount of stabilizer on the particle surface was determined by fluorescence spectroscopy and revealed that the particles are stabilized by a monolayer of BSA-FITC (corresponding to 20 ± 9 molecules), whereas tyrosine forms a multilayered structure consisting of 15900 ± 200 molecules. Desorption experiments show that the BSA-FITC-stabilized particles are ideally suited for application in in vitro and in vivo experiments because the ligand desorption takes several days. Depending on the BSA concentration in the particles surroundings, the rate constant is k = 0.2 per day or lower when applying first order kinetics, that is, 50% of the BSAFITC molecules are released from the particle’s surface within 3.4 days. For illustration, we provide a first application of the fluorescence-labeled particles in an uptake study with two different commonly used cell lines, the human liver cell model HepG2 and the human intestinal cell model of differentiated Caco-2 cells. KW - Small-angle X-ray scattering KW - SAXS KW - Nanoparticle KW - Silver nanoparticles PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452166 DO - https://doi.org/10.1021/acs.langmuir.8b01305 SN - 1520-5827 SN - 0743-7463 VL - 34 IS - 24 SP - 7153 EP - 7160 PB - American Chemical Society AN - OPUS4-45216 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Saloga, Patrick E. J. A1 - Smales, Glen Jacob A1 - Clark, Adam H. A1 - Thünemann, Andreas T1 - Zinc Phosphate Nanoparticles Produced in Saliva N2 - This paper reports the formation of zinc phosphate nanoparticles from the artificial digestion of zinc chloride. Initially, the formation of amorphous primary particles with a mean radius of 1.1 nm is observed, alongside the formation of larger, protein stabilized aggregates. These aggregates, with a radius of gyration of 37 nm, are observed after 5 minutes of exposure to artificial saliva and are shown to be colloidally stable for a minimum time of two weeks. The initially formed primary particles are thought to consist of amorphous zinc phosphate, which is then transformed into crystalline Zn3(PO4)2·4H2O over the course of two weeks. Our results demonstrate that the interaction of inorganic salts with bodily fluids can induce the formation of de novo nanoparticles, which in turn, provides insights into how zinc‐enriched foods may also facilitate the formation of nanoparticles upon contact with saliva. As such, this may be considered as an undesirable (bio)mineralization. KW - SAXS KW - Digestion KW - Zinc phosphate PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514239 DO - https://doi.org/10.1002/ejic.202000521 IS - 38 SP - 3654 EP - 3661 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-51423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Saloga, Patrick E. J. A1 - Kästner, Claudia A1 - Thünemann, Andreas T1 - High-speed but not magic: Microwave-assisted synthesis of ultra-small silver nanoparticles N2 - Reaction procedures have been improved to achieve higher yields and shorter reaction times: one possibility is the usage of microwave reactors. In the literature, this is under discussion, for example, nonthermal effects resulting from the microwave radiation are claimed. Especially for the synthesis of nanomaterials, it is of crucial importance to be aware of influences on the reaction pathway. Therefore, we compare the syntheses of ultra-small silver nanoparticles via conventional and microwave heating. We employed a versatile one-pot polyol synthesis of poly(acrylic acid)-stabilized silver nanoparticles, which display superior catalytic properties. No microwave-specific effects in terms of particle size distribution characteristics, as derived by small-angle X-ray scattering and dynamic light scattering, are revealed. Because of the characteristics of a closed system, microwave reactors give access to elevated temperatures and pressures. Therefore, the speed of particle formation can be increased by a factor of 30 when the reaction temperature is increased from 200 to 250 °C. The particle growth process follows a cluster coalescence mechanism. A postsynthetic incubation step at 250 °C induces a further growth of the particles while the size distribution broadens. Thus, utilization of microwave reactors enables an enormous decrease of the reaction time as well as the opportunity of tuning the particle size. Possibly, decomposition of the stabilizing ligand at elevated temperatures results in reduced yields. A compromise between short reaction times and high yields can be found at a temperature of 250 °C and a corresponding reaction time of 30 s. KW - Silver nanoparticles KW - SAXS KW - Small-angle X-ray scattering KW - Microwave synthesis PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-437028 DO - https://doi.org/10.1021/acs.langmuir.7b01541 SN - 0743-7463 SN - 1520-5827 VL - 34 IS - 1 SP - 147 EP - 153 PB - American Chemical Society CY - Washington, D.C. AN - OPUS4-43702 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kästner, Claudia A1 - Saloga, Patrick E. J. A1 - Thünemann, Andreas T1 - Kinetic monitoring of glutathione-induced silver nanoparticle disintegration N2 - We report on etching of polyacrylic acid-stabilised silver nanoparticles in the presence of glutathione (GSH). The initial particles with a radius of 3.2 nm and consisting of ∼8100 silver atoms dissolve in a two-step reaction mechanism while in parallel smaller silver particles with a radius of 0.65 nm and consisting of 60 to 70 silver atoms were formed. The kinetics of the etching of the initial particles, accompanied by formation of smaller silver particles was interpreted based on in situ, time-resolved small-angle X-ray scattering (SAXS) experiments. KW - Small-angle X-ray scattering KW - SAXS KW - Silver nanoparticles PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452464 DO - https://doi.org/10.1039/c8nr02369g SN - 2040-3372 VL - 10 IS - 24 SP - 11485 EP - 11490 PB - The Royal Society of Chemistry AN - OPUS4-45246 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 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553504 DO - https://doi.org/10.1039/D2NR01648F 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 - Navarro, L. A1 - Thünemann, Andreas A1 - Yokosawa, T. A1 - Spiecker, E. A1 - Klinger, D. T1 - Regioselective Seeded Polymerization in Block Copolymer Nanoparticles: Post-Assembly Control of Colloidal Features N2 - Post-assembly modifications are efficient tools to adjust colloidal features of block copolymer (BCP) particles. However, existing methods often address particle shape, morphology, and chemical functionality individually. For simultaneous control, we transferred the concept of seeded polymerization to phase separated BCP particles. Key to our approach is the regioselective polymerization of (functional) monomers inside specific BCP domains. This was demonstrated in striped PS-b-P2VP ellipsoids. Here, polymerization of styrene preferably occurs in PS domains and increases PS lamellar thickness up to 5-fold. The resulting asymmetric lamellar morphology also changes the particle shape, i.e., increases the aspect ratio. Using 4-vinylbenzyl azide as co-monomer, azides as chemical functionalities can be added selectively to the PS domains. Overall, our simple and versatile method gives access to various multifunctional BCP colloids from a single batch of pre-formed particles. KW - Small-angle X-ray scattering KW - SAXS KW - Nanostructure KW - Polymer KW - Nanoparticle PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557246 DO - https://doi.org/10.1002/anie.202208084 SN - 1433-7851 VL - 61 IS - 35 SP - 1 EP - 11 PB - Wiley CY - Weinheim AN - OPUS4-55724 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 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550741 DO - https://doi.org/10.1186/s43591-022-00036-0 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 - 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 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543731 DO - https://doi.org/10.1021/acsmacrolett.1c00665 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 - Voss, L. A1 - Hoche, E. A1 - Stock, V. A1 - Böhmert, L. A1 - Braeuning, A. A1 - Thünemann, Andreas A1 - Sieg, H. T1 - Intestinal and hepatic effects of iron oxide nanoparticles N2 - Iron oxide nanoparticles gain increasing attention due to their broad industrial use. However, safety concerns exist since their effects on human cells are still under investigation. The presence of iron oxide nanoparticles in the food pigment E172 has been shown recently. Here, we studied four iron oxide nanoparticles, one food pigment E172 and the ionic control FeSO4 regarding dissolution in biological media, uptake and transport, and cellular effects in vitro in human intestinal Caco-2 and HepaRG hepatocarcinoma cells. The iron oxide nanoparticles passed the gastrointestinal passage without dissolution and reached the intestine in the form of particles. Minor uptake was seen into Caco-2 cells but almost no transport to the basolateral site was detected for any of the tested particles. HepaRG cells showed higher particle uptake. Caco-2 cells showed no alterations in reactive oxygen species production, apoptosis, or mitochondrial membrane potential, whereas two particles induced apoptosis in HepaRG cells, and one altered mitochondrial membrane potential at non-cytotoxic concentrations. No correlation between physicochemical particle characteristics and cellular effects was observed, thus emphasizing the Need for case-by-case assessment of iron oxide nanoparticles. KW - Nanoparticles PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521651 DO - https://doi.org/10.1007/s00204-020-02960-7 VL - 95 IS - 3 SP - 895 EP - 905 PB - Springer AN - OPUS4-52165 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 - 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 synchrotron SAXS instrument ranges through addition of a portable, inexpensive USAXS module with vertical rotation axes N2 - Ultra-SAXS can enhance the capabilities of existing synchrotron SAXS/WAXS beamlines. A compact ultra-SAXS module has been developed, which extends the measurable q-range with 0.0015 ≤ q (nm−1) ≤ 0.2, allowing structural dimensions in the range 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. The use of vertical crystal rotation axes (horizontal diffraction) greatly simplifies the construction, at minimal cost to efficiency. In this paper, the design considerations, realization and synchrotron findings are presented. Measurements of silica spheres, an alumina membrane, and a porous carbon catalyst are provided as application examples. KW - X-ray scattering KW - Microstructure KW - Instrumentation KW - SAXS KW - USAXS KW - Nanostructure KW - Combined techniques PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524919 DO - https://doi.org/10.1107/S1600577521003313 SN - 1600-5775 VL - 28 IS - 3 SP - 824 EP - 833 PB - Wiley CY - Oxford AN - OPUS4-52491 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551502 DO - https://doi.org/10.1002/adem.202101276 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 - Paul, Maxi B. A1 - Böhmert, Linda A1 - Thünemann, Andreas A1 - Loeschner, Katrin A1 - Givelet, Lucas A1 - Fahrenson, Christoph A1 - Braeuning, Albert A1 - Sieg, Holger T1 - Influence of artificial digestion on characteristics and intestinal cellular effects of micro-, submicro- and nanoplastics N2 - The production of plastics is rising since they have been invented. Micro, submicro- and nanoplastics are produced intentionally or generated by environmental processes, and constitute ubiquitous contaminants which are ingested orally by consumers. Reported health concerns include intestinal translocation, inflammatory response, oxidative stress and cytotoxicity. Every digestive milieu in the gastrointestinal tract does have an influence on the properties of particles and can cause changes in their effect on biological systems. In this study, we subjected plastic particles of different materials (polylactic acid, polymethylmethacrylate, melamine formaldehyde) and sizes (micro- to nano-range) to a complex artificial digestion model consisting of three intestinal fluid simulants (saliva, gastric and intestinal juice). We monitored the impact of the digestion process on the particles by performing Dynamic Light Scattering, Scanning Electron Microscopy and Asymmetric Flow Field-Flow Fractionation. An in vitro model of the intestinal epithelial barrier was used to monitor cellular effects and translocation behavior of (un)digested particles. In conclusion, artificial digestion decreased cellular interaction and slightly increased transport of all particles across the intestinal barrier. The interaction with organic matter resulted in clear differences in the agglomeration behavior. Moreover, we provide evidence for polymer-, size- and surface-dependent cellular effects of the test particles. KW - Toxicology KW - Nanoparticles KW - Dynamic Light Scattering KW - Nanoplastics KW - Microplastics KW - Reference Method KW - Reference Material PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593947 DO - https://doi.org/10.1016/j.fct.2023.114423 SN - 0278-6915 VL - 184 SP - 1 EP - 16 PB - Elsevier B.V. AN - OPUS4-59394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sieg, Holger A1 - Schaar, Caroline A1 - Fouquet, Nicole A1 - Böhmert, Linda A1 - Thünemann, Andreas A1 - Braeuning, Albert T1 - Particulate iron oxide food colorants (E 172) during artificial digestion and their uptake and impact on intestinal cells N2 - Iron oxide of various structures is frequently used as food colorant (E 172). The spectrum of colors ranges from yellow over orange, red, and brown to black, depending on the chemical structure of the material. E 172 is mostly sold as solid powder. Recent studies have demonstrated the presence of nanoscaled particles in E 172 samples, often to a very high extent. This makes it necessary to investigate the fate of these particles after oral uptake. In this study, 7 differently structured commercially available E 172 food colorants (2 x Yellow FeO(OH), 2 x Red Fe2O3, 1 x Orange Fe2O3 + FeO(OH) and 2 x Black Fe3O4) were investigated for particle dissolution, ion release, cellular uptake, crossing of the intestinal barrier and toxicological impact on intestinal cells. Dissolution was analyzed in water, cell culture medium and artificial digestion fluids. Small-angle X-ray scattering (SAXS) was employed for determination of the specific surface area of the colorants in the digestion fluids. Cellular uptake, transport and toxicological effects were studied using human differentiated Caco-2 cells as an in vitro model of the intestinal barrier. For all materials, a strong interaction with the intestinal cells was observed, albeit there was only a limited dissolution, and no toxic in vitro effects on human cells were recorded. KW - Toxicology KW - Nanoparticles KW - Small-angle X-ray scattering KW - SAXS PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593935 DO - https://doi.org/10.1016/j.tiv.2024.105772 VL - 96 SP - 1 EP - 12 PB - Elsevier BV AN - OPUS4-59393 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hildebrandt, Jana A1 - Thünemann, Andreas T1 - Aqueous Dispersions of Polypropylene: Toward Reference Materials for Characterizing Nanoplastics N2 - Microplastics and nanoplastics pollute the natural environment all over the world, but the full extent of the hazards posed by this waste is unclear. While research on microplastics is well advanced, little work has been done on nanoplastics. This discrepancy is mainly due to the lacking ability to detect nanoplastics in biologically and environmentally relevant matrices. Nanoplastics reference materials can help the development of suitable methods for identifying and quantifying nanoplastics in nature. The aim is to synthesize nanoplastics made from one of the most commonly used plastics, namely polypropylene. An easy way to produce long-term stable aqueous dispersions of polypropylene nanoparticles (nano polypropylene) is reported. The nanoplastic particles, prepared by mechanical breakdown, show a mean hydrodynamic diameter of D h = 180.5 ± 5.8 nm and a polydispersity index of PDI = 0.084 ± 0.02. No surfactant is needed to obtain dispersion which is stable for more than 6 months. The colloidal stability of the surfactant-free nano polypropylene dispersions is explained by their low zeta potential of 𝜻 = −43 ± 2 mV. KW - Nanoparticles KW - Reference Material KW - Nanoplastics PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571799 DO - https://doi.org/10.1002/marc.202200874 SN - 1022-1336 VL - 44 IS - 6 SP - 1 EP - 15 PB - Wiley-VCH CY - Weinheim AN - OPUS4-57179 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stefaniak, A.B. A1 - Hackley, V.A. A1 - Roebben, G. A1 - Ehara, K. A1 - Hankin, S. A1 - Postek, M.T. A1 - Lynch, I. A1 - Fu, W.-E. A1 - Linsinger, T.P.J. A1 - Thünemann, Andreas T1 - Nanoscale reference materials for environmental, health and safety measurements: needs, gaps and opportunities N2 - The authors critically reviewed published lists of nano-objects and their physico-chemical properties deemed important for risk assessment and discussed metrological challenges associated with the development of nanoscale reference materials (RMs). Five lists were identified that contained 25 (classes of) nano-objects; only four (gold, silicon dioxide, silver, titanium dioxide) appeared on all lists. Twenty-three properties were identified for characterisation; only (specific) surface area appeared on all lists. The key themes that emerged from this review were: 1) various groups have prioritised nano-objects for development as 'candidate RMs' with limited consensus; 2) a lack of harmonised terminology hinders accurate description of many nano-object properties; 3) many properties identified for characterisation are ill-defined or qualitative and hence are not metrologically traceable; 4) standardised protocols are critically needed for characterisation of nano-objects as delivered in relevant media and as administered to toxicological models; 5) the measurement processes being used to characterise a nano-object must be understood because instruments may measure a given sample in a different way; 6) appropriate RMs should be used for both accurate instrument calibration and for more general testing purposes (e.g., protocol validation); 7) there is a need to clarify that where RMs are not available, if '(representative) test materials' that lack reference or certified values may be useful for toxicology testing and 8) there is a need for consensus building within the nanotechnology and environmental, health and safety communities to prioritise RM needs and better define the required properties and (physical or chemical) forms of the candidate materials. KW - Engineered nanomaterials KW - Nano-objects KW - Nanoparticles KW - Nanotechnology KW - Reference materials KW - Characterisation KW - Physico-chemical properties KW - Exposure KW - Risk PY - 2013 DO - https://doi.org/10.3109/17435390.2012.739664 SN - 1743-5390 SN - 1743-5404 VL - 7 IS - 8 SP - 1325 EP - 1337 PB - Informa Healthcare CY - London AN - OPUS4-29343 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Advanced Tools in Small-Angle Scattering for Nanotechnology Research T2 - Workshop on Soft Matter and Functional Materials of the HZB Helmholtz Zentrum Berlin CY - Berlin, Germany DA - 2016-12-03 PY - 2016 AN - OPUS4-35027 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lichtenstein, D. A1 - Böhmert, L. A1 - Meyer, Th. A1 - Sieg, H. A1 - Thünemann, Andreas A1 - Loipis, I. E. A1 - Bäuning, A. A1 - Lampen, A. T1 - Core or coating material? What dictates the uptake and translocation of nanoparticles in vitro? N2 - A core-dependent effect on nanoparticle translocation was revealed. Both the uptake and transport of nanoparticles in and through cells should be considered when discussing nanoparticle fate and safety. T2 - 52nd Congress of the European-Societies-of-Toxicology (EUROTOX) CY - Seville, Spain DA - 04.09.2016 KW - Small-angle X-ray scattering KW - SAXS KW - Silver KW - Nanoparticle PY - 2017 DO - https://doi.org/10.1016/j.toxlet.2016.06.1940 SN - 0378-4274 SN - 1879-3169 VL - 258 SP - S267 EP - S268 PB - Elsevier Ltd. AN - OPUS4-40935 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hewel, M. A1 - Siemann, U. A1 - Smarsly, B. A1 - Stribeck, A. A1 - Thünemann, Andreas T1 - Nachruf auf Wilhelm Ruland N2 - Mit Prof. Dr. Wilhelm Ruland starb am 3. Februar 2021 einer der letzten großen Wissenschaftler, welche die Streutheorie nach dem Zweiten Weltkrieg vorangetrieben haben. Sein zentrales Thema war die Streuung an weicher Materie. Hier lieferte er bis ins hohe Alter grundlegende Beiträge, die den Stellenwert seines Leitspruchs demonstrieren: Nichts ist praktischer als eine gute Theorie. KW - SAXS PY - 2021 VL - 20 IS - 4 SP - 50 EP - 50 PB - Wiley AN - OPUS4-52413 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Challenges of synthesis and analysis of core-shell nanoparticles for reference materials N2 - Core-shell nanoparticles are widespread in nature, industrial applications and nanotechnology research. Facile ways of modern synthesis will be discussed and possibilities to reveal their structures with small-angle X-ray scattering (SAXS). A recent review on using block copolymer templates as one of the most reliable routes for tuning size and shape of nanoparticles is provided by Li et al.1 Ferritin and apoferritin are archetypical examples for protein-based core-shell nanoparticles. Their structures are easily accessed by synchrotron SAXS2 but also with commercial instruments and allow fast performance tests.3 SASfit4 is a suitable program tool based on classical curve fitting and McSAS5 is a complementary program based on a Monte Carlo technique. Detailed refinements of SAXS data evaluation are on the way for better data analysis.6 A sub nanometer resolution is state-of-the-art for quantification of the size distribution of polyacrylic acid stabilized silver nanoparticles.3 Such particles are useful in catalysis.7 It was observed that the catalytic activity can be tuned easily by varying the shell material of the particles. T2 - NanoWorkshop 2018 (Workshop on reference nanomaterials, current situation and needs: development, measurement, standardization) CY - Berlin, Germany DA - 14.05.2018 KW - Small-angle X-ray scattering KW - SAXS KW - Nanoparticle PY - 2018 AN - OPUS4-44903 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thünemann, Andreas A1 - Kubowicz, S. A1 - v. Berlepsch, H. A1 - Möhwald, H. T1 - Two-Compartment Micellar Assemblies Obtained via Aqueous Self-Organization of Synthetic Polymer Building Blocks N2 - We synthesized a symmetric linear ABCBA pentablock copolymer consisting of poly(ethylene oxide), poly(-benzyl L-glutamate), and a poly(perfluoro ether) (fluorolink). The different blocks are highly immiscible with each other and form two-compartment micelles of mainly cylindrical shape in aqueous solution with lengths in the range of 100 to 200 nm and diameters of about 24 nm. The poly(perfluoro ether) (C blocks) forms the liquidlike center of the micelles (d = 6 nm). This is surrounded by a first shell of ca. 2 nm thickness consisting of -sheets of poly(-benzyl L-glutamate) (B blocks) and a second 7 nm shell of poly(ethylene oxide) (A blocks). The A blocks provide water solubility, and the B and C blocks form separated hydrophobic compartments. This work is a contribution to the development of multicompartment micelles devoted to mimic transport proteins such as serum albumins in long-term development. KW - Micelles KW - Block-copolymers PY - 2006 DO - https://doi.org/10.1021/la0533720 SN - 0743-7463 SN - 1520-5827 VL - 22 IS - 6 SP - 2506 EP - 2510 PB - American Chemical Society CY - Washington, DC AN - OPUS4-12190 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Maghemite nanoparticles protectively coated with poly(ethylene imine) and poly(ethylene oxide)-block-oly(glutamic acid) T2 - 6th international Conference on Scientific and Clinical Applications of Magnetic Carriers CY - Krems, Austria DA - 2006-05-17 PY - 2006 AN - OPUS4-13829 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - SAXS for the development of reference materials: Silver nanoparticles, a case study N2 - Today there are hundreds of products available containing silver in form of nanoparticles, so-called nanosilver. This situation and the foreseeable future growing market of nanosilver will supposedly cause an increased release of silver into the environment. In this way, silver can be also incorporated into the human body and accumulated in different organs, which can be toxic or at least an unknown risk to human health. For these reasons, it is important to constantly study materials containing silver nanoparticles, their production, application in products and technical processes, dissemination of silver nanoparticles in the environment, and effects on humans and nature. The state-of-the-art nanoparticle size and concentration characterization are illustrated in an extensive interlaboratory comparison. To guarantee the traceability of measurements and to secure the comparison of results of different analytical methods, reference materials (RM) and certified reference materials (CRM) are essential. As a case study, the objective of the presented project was to provide an aqueous suspension of silver nanoparticles as a reference material with a nominal diameter below 10 nm for application in the determination of the size and concentration of nanoparticles in an aqueous surrounding. Measurands are the particles’ diameter D, size distribution width σ, number density N, and concentration c. Target uncertainties, defined as one sigma of the measurand values, are 5% for D, 10% for σ, 20% for N, and 20% for c. The certification was carried out based on ISO 17867 and the relevant ISO-Guides to produce reference material. The process of using SAXS as a reliable method for testing homogeneity and short-term and long-term stability of the material is reported. The particle preparation is described in detail so that the user can carry out the steps of synthesis and characterization in his own laboratory if required. Optionally, one can also contact the author for the provision of the silver nanoparticles. Detailed information can be found elsewhere (BAM Certification Reports, BAM-N008 (2022)). T2 - SAXS excites CY - Graz, Austria DA - 04.04.2023 KW - Nanoparticles KW - SAXS KW - Nanosilver KW - Small-angle x-ray scattering PY - 2023 AN - OPUS4-57283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szczerba, Wojciech A1 - Riesemeier, Heinrich A1 - Thünemann, Andreas T1 - Bond length cntraction in gold nanoparticles N2 - The structure of nanoparticles typically differs from its bulk counterpart. Predominantly, the structures of gold nanoparticles have been under exceedingly intense discussion since the discovery of their high catalytic activity. We found an increasing bond length contraction with decreasing particle size for citrate-stabilized gold nanoparticles in aqueous solution as determined by in situ extended X-ray absorption fine structure (EXAFS) spectroscopy. Particle sizes and size distributions were determined by small-angle X-ray scattering. The analysis of the obtained EXAFS spectra employing ab initio calculations reveals that the Au–Au bond length undergoes a contraction of 2 pm for nanoparticles with a radius of 2.9 nm. NIST reference material RM 8011 gold nanoparticles with a radius of 4.4 nm exhibit a smaller contraction of approximately 1 pm. Finally, gold atoms in RM 8013 particles with a radius of 25.7 nm show distances of 288 pm— identical to the distance in gold foil—and exhibits bulk-like properties. The observed bond length contraction of gold nanoparticles in solution is significantly smaller than previously reported for gold nanoparticle deposited on surfaces, which is up to 15 pm. This indicates that the bond length contraction effect of 'free' and 'surfaceimmobilized' nanoparticles differ fundamentally. Such difference could be essential for the understanding of nanoparticle-supported catalysis. KW - Small-angle X-ray scattering KW - SAXS KW - EXAFS KW - XAFS KW - Nanoparticle KW - Gold PY - 2010 DO - https://doi.org/10.1007/s00216-010-4200-z SN - 1618-2642 SN - 1618-2650 VL - 398 IS - 5 SP - 1967 EP - 1972 PB - Springer CY - Berlin AN - OPUS4-22173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liebig, F. A1 - Sarhan, R. M. A1 - Prietzel, C. A1 - Thünemann, Andreas A1 - Bargheer, M. A1 - Koetz, J. T1 - Undulated Gold Nanoplatelet Superstructures: In Situ Growth of Hemispherical Gold Nanoparticles onto the Surface of Gold Nanotriangles N2 - Negatively charged flat gold nanotriangles, formed in a vesicular template phase and separated by an AOT-micelle-based depletion flocculation, were reloaded by adding a cationic polyelectrolyte, that is, a hyperbranched polyethylenimine (PEI). Heating the system to 100 °C in the presence of a gold chloride solution, the reduction process leads to the formation of gold nanoparticles inside the polymer shell surrounding the nanoplatelets. The gold nanoparticle formation is investigated by UV−vis spectroscopy, small-angle X-ray scattering, and dynamic light scattering measurements in combination with transmission electron microscopy. Spontaneously formed gold clusters in the hyperbranched PEI shell with an absorption maximum at 350 nm grow on the surface of the nanotriangles as hemispherical particles with diameters of ∼6 nm. High-resolution micrographs show that the hemispherical gold particles are crystallized onto the {111} facets on the bottom and top of the platelet as well as on the edges without a grain boundary. Undulated gold nanoplatelet superstructures with special properties become available, which show a significantly modified performance in SERS-detected photocatalysis regarding both reactivity and enhancement factor. KW - Small-angle X-ray scattering KW - SAXS KW - gold KW - nanoparticle PY - 2018 DO - https://doi.org/10.1021/acs.langmuir.7b02898 SN - 0743-7463 VL - 34 IS - 15 SP - 4584 EP - 4594 PB - American Chemical Society AN - OPUS4-44704 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thünemann, Andreas A1 - Schütt, D. A1 - Sachse, R. A1 - Schlaad, H. A1 - Möhwald, H. T1 - Complexes of Poly(ethylene oxide)-block-Poly(L-glutamate) and Diminazene KW - Polymers KW - Nanoparticles KW - Proteins PY - 2006 SN - 0743-7463 SN - 1520-5827 VL - 22 IS - 5 SP - 2323 EP - 2328 PB - American Chemical Society CY - Washington, DC AN - OPUS4-12117 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Structure Analysis of Functional Hydrogels with Small-Angle X-ray Scattering (SAXS) N2 - Hydrogel properties are largely determined by their network structure. Here, we report on the capabilities of SAXS methods for characterizing polymer-network gels. SAXS provides rich insight into different types and levels of nanostructural inhomogeneities in these soft matter materials. The structure analysis of alginate hydrogels, typically utilized in tissue engineering applications, will be discussed in detail. T2 - Polydays 2024 CY - Berlin, Germany DA - 30.09.2024 KW - SAXS KW - Small-angle X-ray scattering KW - Polymer KW - Gel PY - 2024 AN - OPUS4-61184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kaufner, L. A1 - Cartier, R. A1 - Wüstneck, R. A1 - Fichtner, I. A1 - Pietschmann, S. A1 - Bruhn, H. A1 - Schütt, Dagmar A1 - Thünemann, Andreas A1 - Pison, U. T1 - Poly(ethylene oxide)-block-poly(glutamic acid) coated maghemite nanoparticles: in vitro characterization and in vivo behaviour N2 - Positively charged superparamagnetic iron oxide (SPIO) particles of maghemite were prepared in aqueous solution and subsequently stabilized with poly(ethylene oxide)-block-poly(glutamic acid) (PEO–PGA) at a hydrodynamic diameter of 60 nm. Depending on the amount of PEO–PGA used, this is accompanied by a switching of their zeta potentials from positive to negative charge (-33 mV). As a prerequisite for in vivo testing, the PEO–PGA coated maghemite nanoparticles were evaluated to be colloidally stable in water and in physiological salt solution for longer than six months as well in various buffer systems under physiological pH and salt conditions (AFM, dynamic light scattering). We excluded toxic effects of the PEO–PGA coated maghemite nanoparticles. We demonstrated by in vivo MR-imaging and 111In measurements a biodistribution of the nanoparticles into the liver comparable to carboxydextran coated superparamagnetic iron oxide nanoparticles (Resovist®) as a reference nanoscaled MRI contrast medium. This was enforced by a detailed visualization of our nanoparticles by electron microscopy of liver tissue sections. Furthermore, our results indicate that 15% of the injected PEO–PGA coated maghemite nanoparticles circulate in the blood compartment for at least 60 min after i.v. application. KW - Nanotechnology KW - Nano Particle KW - Block-Copolymer PY - 2007 DO - https://doi.org/10.1088/0957-4484/18/11/115710 SN - 0957-4484 SN - 1361-6528 VL - 18 IS - 11 SP - 115710 (1 EP - 10) PB - IOP Publishing Ltd. CY - Bristol AN - OPUS4-16494 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Structures, drug-uptake and drug-release determination of micelles, vesicles, and polymeric nanoparticles with small-angle X-ray scattering T2 - Sino-German Symposium "Nanomaterials for Biomedical Applications" CY - Hangzhou, China DA - 2013-10-27 PY - 2013 AN - OPUS4-29433 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guljamow, A. A1 - Delißen, Friedmar A1 - Baumann, O. A1 - Thünemann, Andreas A1 - Dittmann, E. T1 - Unique properties of eukaryote-type actin and profilin horizontally transferred to cyanobacteria N2 - A eukaryote-type actin and its binding protein profilin encoded on a genomic island in the cyanobacterium Microcystis aeruginosa PCC 7806 co-localize to form a hollow, spherical enclosure occupying a considerable intracellular space as shown by in vivo fluorescence microscopy. Biochemical and biophysical characterization reveals key differences between these proteins and their eukaryotic homologs. Small-angle X-ray scattering shows that the actin assembles into elongated, filamentous polymers which can be visualized microscopically with fluorescent phalloidin. Whereas rabbit actin forms thin cylindrical filaments about 100 µm in length, cyanobacterial actin polymers resemble a ribbon, arrest polymerization at 5-10 µm and tend to form irregular multi-strand assemblies. While eukaryotic profilin is a specific actin monomer binding protein, cyanobacterial profilin shows the unprecedented property of decorating actin filaments. Electron micrographs show that cyanobacterial profilin stimulates actin filament bundling and stabilizes their lateral alignment into heteropolymeric sheets from which the observed hollow enclosure may be formed. We hypothesize that adaptation to the confined space of a bacterial cell devoid of binding proteins usually regulating actin polymerization in eukaryotes has driven the co-evolution of cyanobacterial actin and profilin, giving rise to an intracellular entity. PY - 2012 DO - https://doi.org/10.1371/journal.pone.0029926 SN - 1932-6203 VL - 7 IS - 1 SP - e29926-1 - e29926-11 PB - PubMed Central AN - OPUS4-25403 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - López, J.P. A1 - Kraus, Werner A1 - Reck, Günter A1 - Thünemann, Andreas A1 - Kurth, D.G. T1 - Synthesis, structure and reactivity of the homoleptic iron(II) complex of the novel 4'-(4'''-pyridyl-N-oxide)-2,2':6',2''-terpyridine ligand N2 - The new ligand 4´-(4´´´-pyridyl-N-oxide)-2,2´:6´,2´´-terpyridine (pyNoxterpy) and its homoleptic iron(II) complex have been synthesised, and structural and spectroscopic studies have been carried out. The obtained results have been compared with the reported data for the parent ligand 4´-(4´´´-pyridyl)-2,2´:6´,2´´-terpyridine (pyterpy) and its homoleptic iron(II) complex. Significant differences between the spectral and electrochemical properties of the metal complexes have been found, derived from the changes in the electronic properties of the coordinated ligands. KW - Terpyridine KW - Pyridine N-oxide KW - Iron complexes KW - Crystal structure PY - 2005 SN - 0020-1693 SN - 1873-3255 VL - 358 IS - 12 SP - 3384 EP - 3390 PB - Elsevier Sequoia CY - Lausanne AN - OPUS4-10908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liebig, Ferenc A1 - Moreno, Silvia A1 - Thünemann, Andreas A1 - Temme, Achim A1 - Appelhans, Dietmar A1 - Koetz, Joachim T1 - Toxicological investigations of “naked” and polymer-entrapped AOT-based gold nanotriangles N2 - tNegatively charged ultrathin gold nanotriangles (AuNTs) were synthesized in a vesicular dioctyl sodiumsulfosuccinate (AOT)/phospholipid-based template phase. These “naked” AuNTs with localized surfaceplasmon resonances in the NIR region at about 1300 nm and special photothermal properties are ofparticular interest for imaging and hyperthermia of cancerous tissues. For these kinds of applicationsthe toxicity and the cellular uptake of the AuNTs is of outstanding importance. Therefore, this studyfocuses on the toxicity of “naked” AOT-stabilized AuNTs compared to polymer-coated AuNTs. Poly-meric coating consisted of non-modified hyperbranched poly(ethyleneimine) (PEI), maltose-modifiedpoly(ethyleneimine) (PEI-Mal) and heparin. The toxicological experiments were carried out with twodifferent cell lines (embryonic kidney carcinoma cell line HEK293T and NK-cell leukemia cell line YTS).This study revealed that the heparin-coating of AuNTs improved biocompatibility by a factor of 50 whencompared to naked AuNTs. Of note, the highest nontoxic concentration of the AuNTs coated with PEI andPEI-Mal is drastically decreased. Overall, this is mainly triggered by the different surface charges of poly-meric coatings. Therefore, AuNTs coated with heparin were selected to carry out uptake studies. Theirpromising high biocompatibility and cellular uptake may open future studies in the field of biomedicalapplications. KW - Small-angle X-ray scattering KW - SAXS KW - Nanoparticle PY - 2018 DO - https://doi.org/10.1016/j.colsurfb.2018.04.059 SN - 0927-7765 VL - 167 SP - 560 EP - 567 PB - Elsevier AN - OPUS4-44844 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 DO - 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 - TY - JOUR A1 - Böhmert, L. A1 - Niemann, B. A1 - Thünemann, Andreas A1 - Lampen, A. T1 - Cytotoxicity of peptide-coated silver nanoparticles on the human intestinal cell line Caco-2 N2 - Silver nanoparticles are used in a wide range of consumer products such as clothing, cosmetics, household goods, articles of daily use and pesticides. Moreover, the use of a nanoscaled silver hydrosol has been requested in the European Union for even nutritional purposes. However, despite the wide applications of silver nanoparticles, there is a lack of information concerning their impact on human health. In order to investigate the eVects of silver nanoparticles on human intestinal cells, we used the Caco-2 cell line and peptide-coated silver nanoparticles with deWned colloidal, structural and interfacial properties. The particles display core diameter of 20 and 40 nm and were coated with the small peptide L-cysteine L-lysine L-lysine. Cell viability and proliferation were measured using Promegas CellTiter-Blue® Cell Viability assay, DAPI staining and impedance measurements. Apoptosis was determined by Annexin-V/7AAD staining and FACS analysis, membrane damage with Promegas LDH assay and reactive oxygen species by dichloroXuorescein assay. Exposure of proliferating Caco-2 cells to silver nanoparticle induced decreasing adherence capacity and cytotoxicity, whereby the formation of reactive oxygen species could be the mode of action. The eVects were dependent on particle size (20, 40 nm), doses (5–100 μg/mL) and time of incubation (4–48 h). Apoptosis or membrane damage was not detected. KW - Oral uptake KW - Intestinal cells KW - Peptide-coated silver nanoparticles KW - Cytotoxicity KW - Nanotechnology KW - Small-angle X-ray scattering KW - SAXS PY - 2012 DO - https://doi.org/10.1007/s00204-012-0840-4 SN - 0340-5761 SN - 1432-0738 VL - 86 IS - 7 SP - 1107 EP - 1115 PB - Springer CY - Berlin ; Heidelberg [u.a.] AN - OPUS4-26267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Girod, Matthias A1 - Vogel, Stefanie A1 - Szczerba, Wojciech A1 - Thünemann, Andreas T1 - How temperature determines formation of maghemite nanoparticles N2 - We report on the formation of polymer-stabilized superparamagnetic single-core and multi-core maghemite nanoparticles. The particle formation was carried out by coprecipitation of Fe(II) and Fe(III) sulfate in a continuous aqueous process using a micromixer system. Aggregates containing 50 primary particles with sizes of 2 nm were formed at a reaction temperature of 30 °C. These particles aggregated further with time and were not stable. In contrast, stable single-core particles with a diameter of 7 nm were formed at 80 °C as revealed by small-angle X-ray scattering (SAXS) coupled in-line with the micromixer for particle characterization. X-ray diffraction and TEM confirmed the SAXS results. X-ray absorption near-edge structure spectroscopy (XANES) identified the iron oxide phase as maghemite. KW - Iron Oxide Nanoparticles KW - Micromixer KW - SAXS KW - XANES KW - Carboxydextran KW - Nanotechnology PY - 2015 DO - https://doi.org/10.1016/j.jmmm.2014.09.057 SN - 0304-8853 VL - 380 SP - 163 EP - 167 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-32564 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Obeid, R. A1 - Maltseva, Elena A1 - Thünemann, Andreas A1 - Tanaka, F. A1 - Winnik, F. M. T1 - Temperature response of self-assembled micelles of telechelic hydrophobically modified Poly(2-alkyl-2-oxazoline)s in water N2 - Hydrophobically end-modified (HM) poly(2-ethyl-2-oxazolines) (PEtOx) and poly(2-isopropyl-2-oxazolines) (PiPrOx) bearing an n-octadecyl chain on both termini or on one chain end only were prepared by cationic ring-opening polymerization of 2-ethyl-2-oxazoline and 2-isopropyl-2-oxazoline, respectively, and subsequent end-group modification. The polymers had a molar mass (Mn) ranging from 7000 to 13000 g mol-1, a size distribution Mw/Mn < 1.20, and end-group functionality > 0.97. All polymers, except the semitelechelic sample C18-PiPrOx-OH 13K (Mn = 13000 g mol-1), formed core-shell micelles in cold water with a hydrodynamic radius (RH), measured by dynamic light scattering, between 7 and 12 nm and a core of radius (Rc), determined by analysis of small-angle X-ray scattering (SAXS) data, of ~1.3 nm. Aqueous solutions of all polymers underwent a heat-induced phase transition detected by an increase in solution turbidity at a temperature (Tcp, cloud point) ranging from 32 to 62 °C, depending on polymer structure and size. Temperature-dependent light scattering (LS) measurements and fluorescence depolarization studies with the probe diphenylhexatriene (DPH) revealed that extensive intermicellar bridging takes place in solutions heated in the vicinity of Tcp leading to large assemblies (RH ≥ 1 µm). Further heating caused these assemblies to shrink into objects with RH ~ 300-700 nm, depending on the size and structure of the polymer. The formation of H-bonds between water molecules and the main-chain amide nitrogen atoms imparts distinct features to the flower/star micelles formed by telechelic/semitelechelic PiPrOx and PEtOx, compared to the micelles formed by other hydrophobically end-modified water-soluble polymers, such as poly(ethylene oxide) or poly(N-isopropylacrylamide). PY - 2009 DO - https://doi.org/10.1021/ma802592f SN - 0024-9297 SN - 1520-5835 VL - 42 IS - 6 SP - 2204 EP - 2214 PB - American Chemical Society CY - Washington, DC AN - OPUS4-19115 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lindner, A. A1 - Menzel, Michael A1 - Renz, F. A1 - Kurth, D.G. A1 - Thünemann, Andreas T1 - Metallosupramolecular coordination polyelectrolytes investigated by Mössbauer spectroscopy N2 - Metallosupramolecular coordination polyelectrolytes (MEPEs) based on rigid and flexible ditopic bis-terpyridine ligands and Fe(II) ions are investigated by Mössbauer spectroscopy. We demonstrate the influence of mechanical stress induced by grinding on the structure of MEPE as well as the ability of MEPE to self-repair through recrystallisation. KW - Metallosupramolecular coordination polyelectrolyte KW - Bis-terpyridine KW - Mössbauer spectroscopy KW - Supramolecular chemistry PY - 2005 UR - http://www.edoc.mpg.de/298371 SN - 0304-3843 SN - 1572-9540 VL - 166 IS - 1-4 SP - 465 EP - 468 PB - Kluwer CY - Dordrecht AN - OPUS4-15729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Anwendungen der Fluoreszenz-Spektroskopie T2 - Kolloquium der BASF zum Thema "Funktionale Polymere - Smart Materials" CY - Ludwigshafen am Rhein, Germany DA - 2004-05-17 PY - 2004 AN - OPUS4-3974 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Research Group Nanotechnology for Life Science T2 - Kolloquium des Fraunhofer-Instituts für Angewandte Polymerforschung zur 14. Sitzung des Kuratoriums CY - Potsdam, Germany DA - 2004-06-23 PY - 2004 AN - OPUS4-4009 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ihlenburg, R. B. J. A1 - Mai, T. A1 - Thünemann, Andreas A1 - Baerenwald, R. A1 - Saalwächter, K. A1 - Koetz, J. A1 - Taubert, A. T1 - Sulfobetaine Hydrogels with a Complex Multilength-Scale Hierarchical Structure N2 - Hydrogels with a hierarchical structure were prepared from a new highly water-soluble crosslinker N,N,N′,N′-tetramethyl-N,N′-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and from the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The free radical polymerization of the two compounds is rapid and yields near-transparent hydrogels with sizes up to 5 cm in diameter. Rheology shows a clear correlation between the monomer-to-crosslinker ratio and the storage and loss moduli of the hydrogels. Cryo-scanning electron microscopy, low-field nuclear magnetic resonance (NMR) spectroscopy, and small-angle X-ray scattering show that the gels have a hierarchical structure with features spanning the nanometer to the sub-millimeter scale. The NMR study is challenged by the marked inhomogeneity of the gels and the complex chemical structure of the sulfobetaine monomer. NMR spectroscopy shows how these complications can be addressed via a novel fitting approach that considers the mobility gradient along the side chain of methacrylate-based monomers. KW - Small-angle X-ray scattering KW - SAXS KW - Gel PY - 2021 DO - https://doi.org/10.1021/acs.jpcb.0c10601 SN - 1520-6106 VL - 125 IS - 13 SP - 3398 EP - 3408 PB - American Chemical Society AN - OPUS4-52403 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Structure of (bio)polymers in solution T2 - Helmholtz Graduate School Macromolecular Bioscience: PhD Workshop 2013 CY - Teltow, Germany DA - 2013-04-29 PY - 2013 AN - OPUS4-28308 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Oberemm, A. A1 - Hansen, Ulf A1 - Böhmert, L. A1 - Meckert, C. A1 - Braeuning, A. A1 - Thünemann, Andreas A1 - Lampen, A. T1 - Proteomic responses of human intestinal Caco-2 cells exposed to silver nanoparticles and ionic silver N2 - Even although quite a number of studies have been performed so far to demonstrate nanoparticle-specific effects of substances in living systems, clear evidence of these effects is still under debate. The present study was designed as a comparative proteomic analysis of human intestinal cells exposed to a commercial silver nanoparticle reference material and ions from AgNO3. A two-dimensional gel electrophoresis/MALDI mass spectrometry (MS)-based proteomic analysis was conducted after 24-h incubation of differentiated Caco-2 cells with non-cytotoxic and low cytotoxic silver concentrations (2.5 and 25 µg ml−1 nanosilver, 0.5 and 5 µg ml−1 AgNO3). Out of an overall number of 316 protein spots differentially expressed at a fold change of ≥ 1.4 or ≤ −1.4 in all treatments, 169 proteins could be identified. In total, 231 spots were specifically deregulated in particle-treated groups compared with 41 spots, which were limited to AgNO3-treatments. Forty-four spots (14 %) were commonly deregulated by both types of treatment. A considerable fraction of the proteins differentially expressed after treatment with nanoparticles is related to protein folding, synthesis or modification of proteins as well as cellular assembly and organization. Overlays of networks obtained for particulate and ionic treatments showed matches, indicating common mechanisms of combined particle and ionic silver exposure and exclusive ionic silver treatment. However, proteomic responses of Caco-2 cells treated with higher concentrations of silver species also showed some differences, for example regarding proteins related to fatty acid and energy metabolism, suggesting an induction of also some different molecular mechanisms for particle exposure and ionic treatment. KW - Nanoparticle KW - Nanosilver KW - Silver PY - 2016 DO - https://doi.org/10.1002/jat.3231 SN - 1099-1263 VL - 36 SP - 404 EP - 413 PB - Wiley CY - Chichester AN - OPUS4-35301 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weiss, S. I. A1 - Sieverling, N. A1 - Niclasen, M. A1 - Maucksch, Ch. A1 - Thünemann, Andreas A1 - Möhwald, H. A1 - Reinhardt, D. A1 - Rosenecker, J. A1 - Rudolph, C. T1 - Uronic acids functionalized polyethyleneimine (PEI)-polyethyleneglycol (PEG)-graft-copolymers as novel synthetic gene carriers N2 - In this study, we investigated galacturonic (GalAc)- and mannuronic (ManAc) acids as novel targeting ligands for receptor-mediated gene delivery. GalAc and ManAc were coupled to either polyethyleneimine (PEI) or PEI–polyethyleneglycol (PEG). Furthermore, lactobionic acid (LacAc), which comprises a GalAc-related carbohydrate ring, was coupled to each of the polymers through its open-chain gluconic acid moiety. The molar mass distributions of the polymers were characterized by analytical ultracentrifugation and size exclusion chromatography. PEI-conjugate–pDNA complexes were transfected into HepG2-, HeLa-, and 16HBE14o--cells. Gene expression mediated by GalAc- and LacAc-functionalized PEI-conjugates was lower than for PEI. In contrast, gene expression mediated by ManAc-functionalized PEI-conjugates was up to three orders of magnitude higher than for the other tested PEI-conjugates, in particular for negatively charged gene vectors at low N/P ratios, independent of the cell line. Pre-incubation of cells with an excess of ManAc before transfection significantly inhibited transfection rates only for ManAc-functionalized PEI-conjugates. Coupling of methyl-α-D-mannuronic acid to PEI resulted in significantly lower transfection rates than for ManAc-PEI based complexes. Together with fluorescence microscopy images of fluorescein-labelled ManAc-functionalized dextrans and FACS analyses of cells, these results demonstrate that receptor-mediated endocytosis of ManAc–PEI-conjugate–pDNA complexes via ManAc-specific receptors was involved in gene transfer. In conclusion, ManAc-modification of PEI-polymers represents a novel strategy for receptor-mediated gene delivery which could be promising for in vivo application. KW - Gene therapy KW - Gene transfer KW - Polyethylene oxide KW - Nanoparticle PY - 2006 DO - https://doi.org/10.1016/j.biomaterials.2005.11.011 SN - 0142-9612 VL - 27 IS - 10 SP - 2302 EP - 2312 PB - Elsevier CY - Oxford AN - OPUS4-11678 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mantion, Alexandre A1 - Graf, P. A1 - Florea, I. A1 - Haase, A. A1 - Thünemann, Andreas A1 - Masic, A. A1 - Ersen, O. A1 - Rabu, P. A1 - Meier, W. A1 - Luch, A. A1 - Taubert, A. T1 - Biomimetic synthesis of chiral erbium-doped silver/peptide/silica core-shell nanoparticles (ESPN) N2 - Peptide-modified silver nanoparticles have been coated with an erbium-doped silica layer using a method inspired by silica biomineralization. Electron microscopy and small-angle X-ray scattering confirm the presence of an Ag/peptide core and silica shell. The erbium is present as small Er2O3 particles in and on the silica shell. Raman, IR, UV-Vis, and circular dichroism spectroscopies show that the peptide is still present after shell formation and the nanoparticles conserve a chiral plasmon resonance. Magnetic measurements find a paramagnetic behavior. In vitro tests using a macrophage cell line model show that the resulting multicomponent nanoparticles have a low toxicity for macrophages, even on partial dissolution of the silica shell. KW - Nanoparticle KW - Small-angle X-ray scattering KW - SAXS PY - 2011 DO - https://doi.org/10.1039/c1nr10930h SN - 2040-3364 SN - 2040-3372 VL - 3 IS - 12 SP - 5168 EP - 5179 PB - RSC Publ. CY - Cambridge AN - OPUS4-25422 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, R.H. A1 - Runge, S.A. A1 - Ravelli, V. A1 - Thünemann, Andreas A1 - Mehnert, W. A1 - Souto, E.B. T1 - Cyclosporine-loaded solid lipid nanoparticles (SLN): Drug-lipid physicochemical interactions and characterization of drug incorporation N2 - Solid lipid nanoparticles (SLN) were produced loaded with cyclosporine A in order to develop an improved oral formulation. In this study, the particles were characterized with regard to the structure of the lipid particle matrix, being a determining factor for mode of drug incorporation and drug release. Differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS) measurements were employed for the analysis of the polymorphic modifications and mode of drug incorporation. Particles were produced using Imwitor®900 as lipid matrix (the suspension consisted of 10% particles, 8% Imwitor®900, 2% cyclosporine A), 2.5% Tagat S, 0.5% sodium cholate and 87% water. DSC and WAXS were used to analyse bulk lipid, bulk drug, drug incorporated in the bulk and unloaded and drug-loaded SLN dispersions. The processing of the bulk lipid into nanoparticles was accompanied by a polymorphic transformation from the ß to the α-modification. After production, the drug-free SLN dispersions converted back to ß-modification, while the drug-loaded SLN stayed primarily in α-modification. After incorporation of cyclosporine A into SLN, the peptide lost its crystalline character. Based on WAXS data, it could be concluded that cyclosporine is molecularly dispersed in between the fatty acid chains of the liquid-crystalline α-modification fraction of the loaded SLN. KW - Solid lipid nanoparticles KW - Cyclosporine A KW - Characterization KW - Oral bioavailability KW - Lipid polymorphism PY - 2008 DO - https://doi.org/10.1016/j.ejpb.2007.07.006 SN - 0939-6411 SN - 1873-3441 VL - 68 IS - 3 SP - 535 EP - 544 PB - Elsevier CY - Amsterdam AN - OPUS4-17534 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Advanced Tools in Small-Angle Scattering for Nanotechnology Research T2 - Workshop on Soft Matter and Functional Materials of the HZB Helmholtz-Zentrum Berlin CY - Berlin, Germany DA - 2015-12-03 PY - 2015 AN - OPUS4-35028 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Nanotechnologie for Life Science T2 - Fachtagung der Industrie- und Handelskammer CY - Potsdam, Germany DA - 2003-10-29 PY - 2003 AN - OPUS4-3744 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kathan, M. A1 - Kovaricek, P. A1 - Jurissek, Ch. A1 - Senf, A. A1 - Dallmann, A. A1 - Thünemann, Andreas A1 - Hecht, S. T1 - Control of Imine Exchange Kinetics with Photoswitches to Modulate Self-Healing in Polysiloxane Networks by Light Illumination N2 - Various aldehyde-containing photoswitches have been developed whose reactivity toward amines can be controlled externally. A thermally stable bifunctional diarylethene, which in its ring-closed form exhibits imine formation accelerated by one order of magnitude, was used as a photoswitchable crosslinker and mixed with a commercially available amino-functionalized polysiloxane to yield a rubbery material with viscoelastic and self-healing properties that can be reversibly tuned by irradiation. KW - Polymer KW - Self-healing KW - Rheology KW - Nanotechnology PY - 2016 DO - https://doi.org/10.1002/anie.201605311 SN - 1433-7851 (print) SN - 1521-3773 (online) VL - 55 IS - 44 SP - 13882 EP - 13886 PB - Wiley-VCH Verlag GmbH CY - Weinheim AN - OPUS4-37904 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lichtenstein, D. A1 - Ebmeyer, J. A1 - Knappe, Patrick A1 - Juling, S. A1 - Böhmert, L. A1 - Selve, S. A1 - Niemann, B. A1 - Braeuning, A. A1 - Thünemann, Andreas A1 - Lampen, A. T1 - Impact of food components during in vitro digestion of silver nanoparticles on cellular uptake and cytotoxicity in intestinal cells N2 - Because of the rising application of nanoparticles in food and food-related products, we investigated the influence of the digestion process on the toxicity and cellular uptake of silver nanoparticles for intestinal cells. The main food components – carbohydrates, proteins and fatty acids – were implemented in an in vitro digestion process to simulate realistic conditions. Digested and undigested silver nanoparticle suspensions were used for uptake studies in the well-established Caco-2 model. Small-angle X-ray scattering was used to estimate particle core size, size distribution and stability in cell culture medium. Particles proved to be stable and showed radii from 3.6 to 16.0 nm. Undigested particles and particles digested in the presence of food components were comparably taken up by Caco-2 cells, whereas the uptake of particles digested without food components was decreased by 60%. Overall, these findings suggest that in vivo ingested poly (acrylic acid)-coated silver nanoparticles may reach the intestine in a nanoscaled form even if enclosed in a food matrix. While appropriate for studies on the uptake into intestinal cells, the Caco-2 model might be less suited for translocation studies. Moreover, we show that nanoparticle digestion protocols lacking food components may lead to misinterpretation of uptake studies and inconclusive results. KW - Nanoparticle KW - Nanosilver KW - Silver PY - 2015 DO - https://doi.org/10.1515/hsz-2015-0145 SN - 1431-6730 SN - 1432-0355 SN - 1437-4315 VL - 396 IS - 11 SP - 1255 EP - 1264 PB - De Gruyter CY - Berlin [u.a.] AN - OPUS4-34887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bruzzano, S. A1 - Sieverling, N. A1 - Wieland, Ch. A1 - Jaeger, W. A1 - Thünemann, Andreas A1 - Springer, J. T1 - Cationic polymer grafted starch from nonsymmetrically substituted macroinitiators N2 - The aim of this work was the synthesis of starch macroinitiators for cationic polymer grafted starches that: (i) are free of cationic homopolymer, and (ii) display a high degree of conversion of the cationic monomer. We show that this can be achieved by a free-radical polymerization reaction using the cationic monomer N-methacryloyloxyethyl-N,N-dimethyl-N-benzylammonium chloride (MADAM-BQ) and a new starch-based macroazoinitiator. For this purpose, the acid chloride of 4-tert-butylazo-4-cyanovaleric acid was synthesized and bound covalently to starch (predominantly in the C6 position) to form a nonsymmetrically substituted macroinitiator that was used to polymerize MADAM-BQ in aqueous media. Essentially no MADAM-BQ homopolymer was formed. The initiator decomposes thermally to starch radicals of high reactivity and low-molar mass radicals that do not initiate polymerization. The reason for the different reactivities of the radicals is presumably due to the nonsymmetric constitution of the starch-bound azo groups. The graft polymerization of MADAM-BQ in aqueous solution performs according to an ideal overall kinetic. The structure of the synthesized starch-graft-poly(MADAM-BQ) products is similar to that of block copolymers because of the low radical efficiency of the starch initiators in aqueous solution. Especially, starch substrates with a higher content of azo groups did not lead to graft products with shorter graft distances because the state of solution of these macroinitiators becomes worse and aggregation occurs with an increasing degree of substitution. KW - Starch KW - Azo macroinitiators PY - 2005 DO - https://doi.org/10.1021/ma048063f SN - 0024-9297 SN - 1520-5835 VL - 38 SP - 7251 EP - 7261 PB - American Chemical Society CY - Washington, DC AN - OPUS4-10536 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Small-Angle X-ray Scattering at BAM Federal Institute for Materials Research and Testing T2 - Solution Scattering from Biological Macromolecules CY - Hamburg, Germany DA - 2012-10-17 PY - 2012 AN - OPUS4-26843 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rocha, S. A1 - Thünemann, Andreas A1 - do Carmo Pereira, M. A1 - Coelho, M. A1 - Möhwald, H. A1 - Brezesinski, G. T1 - Influence of fluorinated and hydrogenated nanoparticles on the structure and fibrillogenesis of amyloid beta-peptide N2 - Peptide aggregation in amyloid fibrils is implicated in the pathogenesis of several diseases such as Alzheimer's disease. There is a strong correlation between amyloid fibril formation and a decrease in conformational stability of the native state. Amyloid-β peptide (Aβ), the aggregating peptide in Alzheimer's disease, is natively unfolded. The deposits found in Alzheimer's disease are composed of Aβ fibrillar aggregates rich in β-sheet structure. The influence of fluorinated complexes on the secondary structure and fibrillogenesis of Aβ peptide was studied by circular dichroism (CD) spectroscopy and transmission electron microscopy (TEM). CD spectra show that complexes of polyampholyte and fluorinated dodecanoic acid induce a-helix structure in Aβ, but their hydrogenated analogous lead to β-sheet formation and aggregation. The fluorinated nanoparticles with highly negative zeta potential and hydrophobic fluorinated core have the fundamental characteristics to prevent Aβ fibrillogenesis. KW - Amyloid beta-peptide KW - Circular dichroism KW - Conformation analysis KW - Electron microscopy KW - Fluorinated complexes KW - Nanoparticles PY - 2008 DO - https://doi.org/10.1016/j.bpc.2008.06.010 SN - 0301-4622 SN - 1873-4200 VL - 137 IS - 1 SP - 35 EP - 42 PB - Elsevier CY - Amsterdam AN - OPUS4-17810 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Polymer characterization using hard X-rays for revealing solution and solid state structures T2 - Polydays 2012: Polymers and Light CY - Berlin, Germany DA - 2012-09-30 PY - 2012 AN - OPUS4-26838 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Fast and Reliable in situ Analysis of Dispersions of Magnetic Nanoparticles T2 - Scientific and Clinical Applications of Magnetic Carriers CY - Minneapolis, MN, USA DA - 2012-05-22 PY - 2012 AN - OPUS4-26837 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolb, U. A1 - Büscher, K. A1 - Helm, C.A. A1 - Lindner, A. A1 - Thünemann, Andreas A1 - Menzel, Michael A1 - Higuchi, M. A1 - Kurth, D.G. T1 - The solid-state architecture of a metallosupramolecular polyelectrolyte N2 - Self-assembly of Fe(II) and the ditopic ligand 1,4-bis(2,2':6',2"-terpyridine-4'-yl)benzene results in equilibrium structures in solutions, so-called metallosupramolecular coordination polyelectrolytes (MEPEs). It is exceedingly difficult to characterize such macromolecular assemblies, because of the dynamic nature. Therefore, hardly any structural information is available for this type of material. Here, we show that from dilute solutions, where small aggregates predominate, it is possible to grow nanoscopic crystals at an interface. A near atomic resolution structure of MEPE is obtained by investigating the nanoscopic crystals with electron diffraction in combination with molecular modeling. The analysis reveals a primitive monoclinic unit cell (P21/c space group, a = 10.4 Å, b = 10.7 Å, c = 34.0 Å, α = γ = 90°, β = 95°, ρ = 1.26 g/cm³, and Z = 4). The MEPE forms linear rods, which are organized into sheets. Four sheets intersect the unit cell, while adjacent sheets are rotated by 90° with respect to each other. The pseudooctahedral coordination geometry of the Fe(II) centers is confirmed by Mössbauer spectroscopy. The combination of diffraction and molecular modeling presented here may be of general utility to address problems in structural materials science. KW - Polymer KW - Polyelectrolyte KW - Electron diffraction KW - Mössbauer spectroscopy KW - Molecular modeling KW - Supramolecular chemistry PY - 2006 SN - 0027-8424 SN - 1091-6490 VL - 103 IS - 27 SP - 10202 EP - 10206 PB - National Academy of Sciences CY - Washington, DC AN - OPUS4-12495 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Characterization of (bio)macromolecules and polymeric materials with modern scattering methods N2 - The analysis of polymers, biopolymers and polymeric materials is of great interest in biomaterials science. Here small-angle x-ray scattering (SAXS), static light scatterin (SLS) and dynamic light scattering (DLS) are described. Current efforts for digitalization of this methods are explaind with respect to modern data science in biomedical research. T2 - MacroBio Summer School 2018: Biomaterial Science in View of Digitalization CY - Teltow, Germany DA - 24.09.2018 KW - Small-angle x-ray scattering KW - SAXS KW - Static light scattering KW - SLS KW - Dynamic light scattering KW - DLS KW - Biomaterials PY - 2018 AN - OPUS4-46051 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kästner, Claudia A1 - Lampen, A. A1 - Thünemann, Andreas T1 - What happens to the silver ions? – Silver thiocyanate nanoparticle formation in an artificial digestion N2 - An artificial digestion of silver nitrate is reported. It is shown that AgSCN nanoparticles emerge from ionic silver in saliva and remain present during the entire digestion process. The particles were characterized by infrared spectroscopy and small- and wide-angle X-ray scattering (SAXS/WAXS) regarding their composition and size distribution. KW - SAXS KW - WAXS KW - Artificial digestion PY - 2018 DO - https://doi.org/10.1039/c7nr08851e SN - 2040-3364 SN - 2040-3372 VL - 10 IS - 8 SP - 3650 EP - 3653 PB - RSC Publ. CY - Cambridge AN - OPUS4-44277 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bruemmel, Y. A1 - Chan, C. A1 - Renneberg, R. A1 - Thünemann, Andreas A1 - Seydack, M. T1 - On the Influence of Different Surfaces in Nano- and Submicrometer Particle Based Fluorescence Immunoassays KW - Nanoparticles KW - Fluorescence immuno assays PY - 2004 DO - https://doi.org/10.1021/la0486032 SN - 0743-7463 SN - 1520-5827 VL - 20 IS - 21 SP - 9371 EP - 9379 PB - American Chemical Society CY - Washington, DC AN - OPUS4-4573 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stutz, C. A1 - Bilecka, I. A1 - Thünemann, Andreas A1 - Niederberger, M. A1 - Börner, H.G. T1 - Superparamagnetic core-shell nanoparticles as solid supports for peptide synthesis N2 - Functional superparamagnetic core–shell nanoparticles are synthesized by a microwave assisted route and can be used as colloidal supports for peptide synthesis in 'quasi solution'. KW - Nanotechnology KW - Small-angle X-ray scatering KW - SAXS PY - 2012 DO - https://doi.org/10.1039/c2cc33492e SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x VL - 48 IS - 57 SP - 7176 EP - 7178 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-26116 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Laschewsky, A. A1 - Mertoglu, M. A1 - Kubowicz, S. A1 - Thünemann, Andreas T1 - Lamellar Structured Nanoparticles Formed by Complexes of a Cationic Block Copolymer and Perfluorodecanoic Acid N2 - A double hydrophilic block copolymer was synthesized by controlled free radical polymerization, namely by the RAFT method, from a poly(ethylene oxide) macromonomer and a cationic acrylate. Stoichiometric complexes with sodium decanoate and with sodium perfluorodecanoate were prepared by self-assembly. Both complexes are soluble in water forming core-shell nanoparticles with hydrodynamic radii of 54 and 22 nm, respectively, and neutral potentials. The complex containing decanoate decomposed upon dilution, while the complex with perfluorodecanoate is stable even against dialysis and in salt solution. Only the nanoparticles containing perfluorodecanoate show a strong contrast in small-angle X-ray scattering (SAXS). It is produced from their cores that have an elliptical shape (short axes = 8.5 nm, long axis = 23.3 nm) and a sharp density transition to the shell. The cores exhibit an internal lamellar structure with a long period of 3.65 nm consisting of fluorocarbon rich lamellae (d1 = 3.00 nm) and lamellae enriched in ionic groups (d2 = 0.65 nm). These fluorinated nanoparticles coexist in physiological buffer with human serum albumin and fibrinogen without inducing aggregation. Moreover, the content of -helix of these serum proteins increased when in solution with the fluorinated nanoparticles. KW - Small-angle X-ray scattering (SAXS) KW - Block-copolymers KW - Polymeric nanoparticles KW - Protein secondary structure PY - 2006 DO - https://doi.org/10.1021/ma061573k SN - 0024-9297 SN - 1520-5835 VL - 39 IS - 26 SP - 9337 EP - 9345 PB - American Chemical Society CY - Washington, DC AN - OPUS4-14392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Small-Angle X-ray Scattering for Nanoparticle Analysis: The Renaissance of an Ancient Method T2 - Workshop of the Max Planck Institute of Colloids and Interfaces on "Trends in Colloid and Interface Science" CY - Potsdam, Germany DA - 2009-06-12 PY - 2009 AN - OPUS4-19376 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tyagi, R. A1 - Malhotra, S. A1 - Thünemann, Andreas A1 - Sedighi, A. A1 - Weber, M. A1 - Schäfer, A. A1 - Haag, R. T1 - Investigations of host-guest interactions with shape-persistent nonionic dendritic micelles N2 - The interaction of self-assembled dendritic amphiphiles with drugs and dyes in aqueous solutions is of great significance for designing and optimizing shape-persistent delivery systems. Here we present deeper insight for two examples of low molecular weight (LMW) nonionic dendritic amphiphiles as host molecules and a series of selected aromatic guest model molecules (benzene, naphthalene, biphenyl, terphenyl, anthracene, and pyrene). Aromatic guest molecules were incorporated into the self-assemblies of dendritic nanocarriers, and the resultant complexes were studied by a combination of UV, NMR, computational simulation, and small-angle X-ray-scattering (SAXS) techniques in order to determine the loading capacity, localization, and specific interactions in dendritic amphiphiles with guest molecules. Our findings revealed that the localization of guest molecules in the hydrophobic region and the loading capacity of guest molecules are dependent on their size and the arrangement of aromatic rings instead of the loading amount. Furthermore, the shape of self-assembled host molecules was found to be ellipsoidal and highly persistent even after loading the guest molecules. To the best of our knowledge, this is the first systematic host–guest study, particularly with low molecular weight nonionic dendritic amphiphilies and aromatic guest molecules. Thus, this study opens new possibilities and ways to explore the transport behavior of aromatic drugs with such nanocarriers. KW - Nanotechnology PY - 2013 DO - https://doi.org/10.1021/jp401503y SN - 1932-7447 SN - 1089-5639 VL - 117 IS - 23 SP - 12307 EP - 12317 PB - Soc. CY - Washington, DC AN - OPUS4-28710 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fortes Martin, R. A1 - Thünemann, Andreas A1 - Stockmann, Jörg Manfred A1 - Radnik, Jörg A1 - Koetz, J. T1 - From Nanoparticle Heteroclusters to Filament Networks by Self-Assembly at the Water–Oil Interface of Reverse Microemulsions N2 - Surface self-assembly of spherical nanoparticles of sizes below 10 nm into hierarchical heterostructures is under arising development despite the inherent difficulties of obtaining complex ordering patterns on a larger scale. Due to template-mediated interactions between oil-dispersible superparamagnetic nanoparticles (MNPs) and polyethylenimine-stabilized gold nanoparticles (Au(PEI)NPs) at the water–oil interface of microemulsions, complex nanostructured films can be formed. Characterization of the reverse microemulsion phase by UV–vis absorption revealed the formation of heteroclusters from Winsor type II phases (WPII) using Aerosol-OT (AOT) as the surfactant. SAXS measurements verify the mechanism of initial nanoparticle clustering in defined dimensions. XPS suggested an influence of AOT at the MNP surface. Further, cryo-SEM and TEM visualization demonstrated the elongation of the reverse microemulsions into cylindrical, wormlike structures, which subsequently build up larger nanoparticle superstructure arrangements. Such WPII phases are thus proven to be a new form of soft template, mediating the self-assembly of different nanoparticles in hierarchical network-like filaments over a substrate during solvent evaporation. KW - Small-angle X-ray scattering KW - SAXS KW - Nanoparticle KW - Nano structure PY - 2021 DO - https://doi.org/10.1021/acs.langmuir.1c01348 VL - 37 IS - 29 SP - 8876 EP - 8885 PB - American Chemical Society AN - OPUS4-53034 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 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546803 DO - https://doi.org/10.1038/s41598-022-09774-w 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 - Klimakow, Maria A1 - Klobes, Peter A1 - Thünemann, Andreas A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Mechanochemical synthesis of metal-organic frameworks: A fast and facile approach toward quantitative yields and high specific surface areas N2 - The strategy of utilizing mechanochemical synthesis to obtain metal–organic frameworks (MOFs) with high surface areas is demonstrated for two model systems. The compounds HKUST-1 (Cu3(BTC)2, BTC = 1,3,5-benzenetricarboxylate) and MOF-14 (Cu3(BTB)2, BTB = 4,4',4''-benzenetribenzoate) were synthesized by ball milling and characterized by powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and thermal analysis (DTA/DTG/MS). The specific surface area (SSA) of both compounds was characterized by nitrogen adsorption. To verify these results and to understand how the synthetic conditions influence the pore structure and the surface area, additional small-angle X-ray scattering (SAXS) experiments were carried out. Our investigations confirm that this synthesis approach is a promising alternative method for distinct MOFs. This facile method leads to materials with surface areas of 1713 m²/g, which is comparable to the highest given values in the literature for the respective compounds. KW - Metal-organic frameworks KW - Mechanochemistry KW - Green-chemistry synthesis KW - Gas adsorption KW - SAXS KW - Specific surface area PY - 2010 DO - https://doi.org/10.1021/cm1012119 SN - 0897-4756 SN - 1520-5002 VL - 22 IS - 18 SP - 5216 EP - 5221 PB - American Chemical Society CY - Washington, DC AN - OPUS4-21999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, B. A1 - Meyer, T. A1 - Sieg, H. A1 - Kästner, Claudia A1 - Reichardt, P. A1 - Tentschert, J. A1 - Jungnickel, H. A1 - Estrela-Lopis, I. A1 - Burel, A. A1 - Chevance, S. A1 - Gauffre, F. A1 - Jalili, P. A1 - Meijer, J. A1 - Böhmert, L. A1 - Braeuning, A. A1 - Thünemann, Andreas A1 - Emmerling, Franziska A1 - Fessard, V. A1 - Laux, P. A1 - Lampen, A. A1 - Luch, A. T1 - Characterization of aluminum, aluminum oxide and titanium dioxide nanomaterials using a combination of methods for particle surface and size analysis N2 - The application of appropriate analytical techniques is essential for nanomaterial (NM) characterization. In this study, we compared different analytical techniques for NM analysis. Regarding possible adverse health effects, ionic and particulate NM effects have to be taken into account. As NMs behave quite differently in physiological media, special attention was paid to techniques which are able to determine the biosolubility and complexation behavior of NMs. Representative NMs of similar size were selected: aluminum (Al0) and aluminum oxide (Al2O3), to compare the behavior of metal and metal oxides. In addition, titanium dioxide (TiO2) was investigated. Characterization techniques such as dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) were evaluated with respect to their suitability for fast characterization of nanoparticle dispersions regarding a particle's hydrodynamic diameter and size distribution. By application of inductively coupled plasma mass spectrometry in the single particle mode (SP-ICP-MS), individual nanoparticles were quantified and characterized regarding their size. SP-ICP-MS measurements were correlated with the information gained using other characterization techniques, i.e. transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The particle surface as an important descriptor of NMs was analyzed by X-ray diffraction (XRD). NM impurities and their co-localization with biomolecules were determined by ion beam microscopy (IBM) and confocal Raman microscopy (CRM). We conclude advantages and disadvantages of the different techniques applied and suggest options for their complementation. Thus, this paper may serve as a practical guide to particle characterization techniques. KW - Small-angle X-ray scattering KW - SAXS PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-447057 DO - https://doi.org/10.1039/C8RA00205C SN - 2046-2069 VL - 8 IS - 26 SP - 14377 EP - 14388 PB - The Royal Society of Chemistry AN - OPUS4-44705 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Thünemann, Andreas A1 - Emmerling, Franziska A1 - Hodoroaba, Vasile-Dan T1 - Review of existing calibration or reference N2 - We report on calibration standards of nanoparticles meeting the definition of a nanomaterial given by the European Commission (EU 2011) which are relevant for the characterisation methods applied in the NanoDefine project. We found that the Impact of nanoparticles is outstanding in the scientific literature. A number of 270.000 paper titles on nanoparticles are listed in the Web of Science data base. But surprisingly, the availability of suitable certified standard reference materials is scarce. Only a few sources were found. For example, BAM provides the database Nanoscaled Reference Materials at http://www.nano-refmat.bam.de/en/ in cooperation with the ISO/TC 229 Nanotechnologies. In addition, two publications from 2013 on nanoscale reference materials are available. Candidates of nano-(certified) reference materials from other ongoing or just finished FP6 and FP7 nano-metrology projects have been extracted from the Compendium of Projects in the European NanoSafety Cluster (Compendium NSC, 2013). Recommendations for selection of representative test materials and calibration standards for NanoDefine internal tasks, respectively, are also given. KW - Nanomaterial KW - Reference materials KW - Certified reference materials PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389836 UR - http://www.nanodefine.eu/index.php/downloads/nanodefine-technical-reports SP - 1 EP - 18 CY - Wageningen, The Netherlands AN - OPUS4-38983 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Polte, Jörg A1 - Erler, Robert A1 - Thünemann, Andreas A1 - Sokolov, S. A1 - Ahner, T. T. A1 - Rademann, K. A1 - Emmerling, Franziska A1 - Kraehnert, R. T1 - Nucleation and growth of gold nanoparticles studies via in situ small angle X-ray scattering at millisecond time resolution N2 - Gold nanoparticles (AuNP) were prepared by the homogeneous mixing of continuous flows of an aqueous tetrachloroauric acid solution and a sodium borohydride solution applying a microstructured static mixer. The online characterization and screening of this fast process (~2 s) was enabled by coupling a micromixer operating in continuous-flow mode with a conventional in-house small angle X-ray scattering (SAXS) setup. This online characterization technique enables the time-resolved investigation of the growth process of the nanoparticles from an average radius of ca. 0.8 nm to about 2 nm. To the best of our knowledge, this is the first demonstration of a continuous-flow SAXS setup for time-resolved studies of nanoparticle formation mechanisms that does not require the use of synchrotron facilities. In combination with X-ray absorption near edge structure microscopy, scanning electron microscopy, and UV-vis spectroscopy the obtained data allow the deduction of a two-step mechanism of gold nanoparticle formation. The first step is a rapid conversion of the ionic gold precursor into metallic gold nuclei, followed by particle growth via coalescence of smaller entities. Consequently it could be shown that the studied synthesis serves as a model system for growth driven only by coalescence processes. KW - Nanoparticle formation mechanism KW - SAXS KW - Microstructured static mixer KW - Continuous flow PY - 2010 DO - https://doi.org/10.1021/nn901499c SN - 1936-0851 VL - 4 IS - 2 SP - 1076 EP - 1082 PB - ACS Publ. CY - Washington, DC, USA AN - OPUS4-20940 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Breßler, Ingo A1 - Kohlbrecher, J. A1 - Thünemann, Andreas T1 - SASfit: a tool for small-angle scattering data analysis using a library of analytical expressions N2 - SASfit is one of the mature programs for small-angle scattering data analysis and has been available for many years. This article describes the basic data processing and analysis workflow along with recent developments in the SASfit program package (version 0.94.6). They include (i) advanced algorithms for reduction of oversampled data sets, (ii) improved confidence assessment in the optimized model parameters and (iii) a flexible plug-in system for custom user-provided models. A scattering function of a mass fractal model of branched polymers in solution is provided as an example for implementing a plug-in. The new SASfit release is available for major platforms such as Windows, Linux and MacOS. To facilitate usage, it includes comprehensive indexed documentation as well as a web-based wiki for peer collaboration and online videos demonstrating basic usage. The use of SASfit is illustrated by interpretation of the small-angle X-ray scattering curves of monomodal gold nanoparticles (NIST reference material 8011) and bimodal silica nanoparticles (EU reference material ERM-FD-102). KW - Small-angle X-ray scattering KW - Small-angle neutron scattering KW - Curve fitting KW - Nanotechnology KW - Nanoparticles KW - Polymers KW - SAXS PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-343348 DO - https://doi.org/10.1107/S1600576715016544 SN - 0021-8898 SN - 1600-5767 VL - 48 SP - 1587 EP - 1598 PB - Blackwell CY - Oxford AN - OPUS4-34334 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Breßler, Ingo A1 - Pauw, Brian Richard A1 - Thünemann, Andreas T1 - McSAS: software for the retrieval of model parameter distributions from scattering patterns N2 - A user-friendly open-source Monte Carlo regression package (McSAS) is presented, which structures the analysis of small-angle scattering (SAS) using uncorrelated shape-similar particles (or scattering contributions). The underdetermined problem is solvable, provided that sufficient external information is available. Based on this, the user picks a scatterer contribution model (or 'shape') from a comprehensive library and defines variation intervals of its model parameters. A multitude of scattering contribution models are included, including prolate and oblate nanoparticles, core-shell objects, several polymer models, and a model for densely packed spheres. Most importantly, the form-free Monte Carlo nature of McSAS means it is not necessary to provide further restrictions on the mathematical form of the parameter distribution; without prior knowledge, McSAS is able to extract complex multimodal or odd-shaped parameter distributions from SAS data. When provided with data on an absolute scale with reasonable uncertainty estimates, the software outputs model parameter distributions in absolute volume fraction, and provides the modes of the distribution (e.g. mean, variance etc.). In addition to facilitating the evaluation of (series of) SAS curves, McSAS also helps in assessing the significance of the results through the addition of uncertainty estimates to the result. The McSAS software can be integrated as part of an automated reduction and analysis procedure in laboratory instruments or at synchrotron beamlines. KW - Nanotechnology KW - Nanoparticles KW - Small-angle X-ray scattering KW - SAXS PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-334396 DO - https://doi.org/10.1107/S1600576715007347 SN - 0021-8898 SN - 1600-5767 VL - 48 IS - 3 SP - 962 EP - 969 PB - Blackwell CY - Oxford AN - OPUS4-33439 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Polte, Jörg A1 - Tuaev, X. A1 - Wuithschick, M. A1 - Fischer, A. A1 - Thünemann, Andreas A1 - Rademann, K. A1 - Kraehnert, R. A1 - Emmerling, Franziska T1 - Formation mechanism of colloidal silver nanoparticles: analogies and differences to the growth of gold nanoparticles N2 - The formation mechanisms of silver nanoparticles using aqueous silver perchlorate solutions as precursors and sodium borohydride as reducing agent were investigated based on time-resolved in situ experiments. This contribution addresses two important issues in colloidal science: (i) differences and analogies between growth processes of different metals such as gold and silver and (ii) the influence of a steric stabilizing agent on the growth process. The results reveal that a growth due to coalescence is a fundamental growth principle if the monomer-supplying chemical reaction is faster than the actual particle formation. KW - Silver nanoparticle growth KW - Formation mechanisms KW - Nucleation KW - SAXS PY - 2012 DO - https://doi.org/10.1021/nn301724z SN - 1936-0851 VL - 6 IS - 7 SP - 5791 EP - 5802 PB - ACS Publ. CY - Washington, DC, USA AN - OPUS4-26427 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bienert, Ralf A1 - Emmerling, Franziska A1 - Thünemann, Andreas T1 - The size distribution of 'gold standard' nanoparticles N2 - The spherical gold nanoparticle reference materials RM 8011, RM 8012, and RM 8013, with a nominal radius of 5, 15, and 30 nm, respectively, have been available since 2008 from NIST. These materials are recommended as standards for nanoparticle size measurements and for the study of the biological effects of nanoparticles, e.g., in pre-clinical biomedical research. We report on determination of the size distributions of these gold nanoparticles using different small-angle X-ray scattering (SAXS) instruments. Measurements with a classical Kratky type SAXS instrument are compared with a synchrotron SAXS technique. Samples were investigated in situ, positioned in capillaries and in levitated droplets. The number-weighted size distributions were determined applying model scattering functions based on (a) Gaussian, (b) log-normal, and (c) Schulz distributions. The mean radii are 4.36 ± 0.04 nm (RM 8011), 12.20 ± 0.03 nm (RM 8012), and 25.74 ± 0.27 nm (RM 8013). Low polydispersities, defined as relative width of the distributions, were detected with values of 0.067 ± 0.006 (RM 8011), 0.103 ± 0.003, (RM 8012), and 0.10 ± 0.01 (RM 8013). The results are in agreement with integral values determined from classical evaluation procedures, such as the radius of gyration (Guinier) and particle volume (Kratky). No indications of particle aggregation and particle interactions-repulsive or attractive-were found. We recommend SAXS as a standard method for a fast and precise determination of size distributions of nanoparticles. KW - Small-angle scattering KW - Reference materials KW - Metrology KW - Nanoparticles PY - 2009 DO - https://doi.org/10.1007/s00216-009-3049-5 SN - 1618-2642 SN - 1618-2650 VL - 395 IS - 6 SP - 1651 EP - 1660 PB - Springer CY - Berlin AN - OPUS4-20473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pauw, Brian Richard A1 - Smales, Glen Jacob A1 - Anker, A. S. A1 - Annadurai, V. A1 - Balazs, D. M. A1 - Bienert, Ralf A1 - Bouwman, W. G. A1 - Breßler, Ingo A1 - Breternitz, J. A1 - Brok, E. S. A1 - Bryant, G. A1 - Clulow, A. J. A1 - Crater, E. R. A1 - De Geuser, F. A1 - Del Giudice, A. A1 - Deumer, J. A1 - Disch, S. A1 - Dutt, S. A1 - Frank, K. A1 - Fratini, E. A1 - Garcia, P. R. A. F. A1 - Gilbert, E. P. A1 - Hahn, Marc Benjamin A1 - Hallett, J. A1 - Hohenschutz, M. A1 - Hollamby, M. A1 - Huband, S. A1 - Ilavsky, J. A1 - Jochum, J. K. A1 - Juelsholt, M. A1 - Mansel, B. W. A1 - Penttilä, P. A1 - Pittkowski, R. K. A1 - Portale, G. A1 - Pozzo, L. D. A1 - Rochels, L. A1 - Rosalie, Julian A1 - Saloga, Patrick E. J. A1 - Seibt, S. A1 - Smith, A. J. A1 - Smith, G. N. A1 - Spiering, G. A. A1 - Stawski, Tomasz M. A1 - Taché, O. A1 - Thünemann, Andreas A1 - Toth, K. A1 - Whitten, A. E. A1 - Wuttke, J. T1 - The human factor - Results of a small-angle scattering data analysis round robin N2 - A round-robin study has been carried out to estimate the impact of the human element in small-angle scattering data analysis. Four corrected datasets were provided to participants ready for analysis. All datasets were measured on samples containing spherical scatterers, with two datasets in dilute dispersions and two from powders. Most of the 46 participants correctly identified the number of populations in the dilute dispersions, with half of the population mean entries within 1.5% and half of the population width entries within 40%. Due to the added complexity of the structure factor, far fewer people submitted answers on the powder datasets. For those that did, half of the entries for the means and widths were within 44 and 86%, respectively. This round-robin experiment highlights several causes for the discrepancies, for which solutions are proposed. KW - Round Robin KW - Data analysis KW - Small-angle scattering KW - Nanomaterials KW - Interlaboratory comparability KW - Nanostructure quantification KW - Methodology KW - MOUSE PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587091 DO - https://doi.org/10.1107/S1600576723008324 SN - 1600-5767 VL - 56 IS - 6 SP - 1618 EP - 1629 PB - Wiley-Blackwell CY - Oxford AN - OPUS4-58709 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Pauw, Brian Richard A1 - Smales, Glen Jacob A1 - Anker, A. S. A1 - Balazs, D. M. A1 - Beyer, F. L. A1 - Bienert, Ralf A1 - Bouwman, W. G. A1 - Breßler, Ingo A1 - Breternitz, J. A1 - Brok, E. S. A1 - Bryant, G. A1 - Clulow, A. J. A1 - Crater, E. R. A1 - De Geuser, F. A1 - Giudice, A. D. A1 - Deumer, J. A1 - Disch, S. A1 - Dutt, S. A1 - Frank, K. A1 - Fratini, E. A1 - Gilbert, E. P. A1 - Hahn, Marc Benjamin A1 - Hallett, J. A1 - Hohenschutz, Max A1 - Hollamby, M. J. A1 - Huband, S. A1 - Ilavsky, J. A1 - Jochum, J. K. A1 - Juelsholt, M. A1 - Mansel, B. W. A1 - Penttilä, P. A1 - Pittkowski, R. K. A1 - Portale, G. A1 - Pozzo, L. D. A1 - Ricardo de Abreu Furtado Garcia, P. A1 - Rochels, L. A1 - Rosalie, Julian A1 - Saloga, P. E. J. A1 - Seibt, S. A1 - Smith, A. J. A1 - Smith, G. N. A1 - Annadurai, V. A1 - Spiering, G. A. A1 - Stawski, Tomasz A1 - Taché, O. A1 - Thünemann, Andreas A1 - Toth, K. A1 - Whitten, A. E. A1 - Wuttke, J. T1 - The human factor - Results of a small-angle scattering data analysis round robin N2 - A Round Robin study has been carried out to estimate the impact of the human element in small-angle scattering data analysis. Four corrected datasets were provided to participants ready for analysis. All datasets were measured on samples containing spherical scatterers, with two datasets in dilute dispersions, and two from powders. Most of the 46 participants correctly identified the number of populations in the dilute dispersions, with half of the population mean entries within 1.5 % and half of the population width entries within 40 %, respectively. Due to the added complexity of the structure factor, much fewer people submitted answers on the powder datasets. For those that did, half of the entries for the means and widths were within 44 % and 86 % respectively. This Round Robin experiment highlights several causes for the discrepancies, for which solutions are proposed. KW - Round robin KW - Sall-angle scattering KW - Nanostructure quantification KW - Nanostructure KW - SAXS KW - MOUSE KW - X-ray scattering KW - Size distribution KW - Nanoparticles PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571342 DO - https://doi.org/10.48550/arXiv.2303.03772 SP - 1 EP - 23 PB - Cornell University CY - Ithaca, NY AN - OPUS4-57134 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Wolf, Jako A1 - Stawski, Tomasz A1 - Smales, Glen Jacob A1 - Thünemann, Andreas A1 - Emmerling, Franziska T1 - SI Files for "Towards automation of the polyol process for the synthesis of silver nanoparticles" N2 - The graphml file: reaction_graph_AgNP.graphml is included. It contains topological information (Fig. 1 in the main text) about the reaction setup and metadata with reaction condtions. It used by the Python API used to control the Chemputer. SAXS reports. The complete report sheets generated by McSAS are included. They contain extended information characterising the size distributions and the fitting parameters. NP3_I: saxs_report_NP3_I.pdf NP3_II: saxs_report_NP3_II.pdf NP3_III: saxs_report_NP3_III.pdf NP3_IV: saxs_report_NP3_IV.pdf NP5_I: saxs_report_NP5_I.pdf NP5_II: saxs_report_NP5_II.pdf NP5_III: saxs_report_NP5_III.pdf KW - Automated synthesis KW - Silver KW - Nanoparticles PY - 2022 DO - https://doi.org/10.5281/zenodo.5910614 PB - Zenodo CY - Geneva AN - OPUS4-55197 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Polte, Jörg A1 - Ahner, T. T. A1 - Delißen, Friedmar A1 - Sokolov, S. A1 - Emmerling, Franziska A1 - Thünemann, Andreas A1 - Kraehnert, R. T1 - Mechanism of gold nanoparticle formation in the classical citrate synthesis method derived from coupled in situ XANES and SAXS evaluation PY - 2010 DO - https://doi.org/10.1021/ja906506j SN - 0002-7863 SN - 1520-5126 VL - 132 IS - 4 SP - 1296 EP - 1301 PB - American Chemical Society CY - Washington, DC AN - OPUS4-23048 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thünemann, Andreas A1 - Kegel, Jenny A1 - Polte, Jörg A1 - Emmerling, Franziska T1 - Superparamagnetic Maghemite Nanorods: Analysis by Coupling Field-Flow Fractionation and Small-Angle X-ray Scattering N2 - We report on the online coupling of asymmetrical flow field-flow fractionation (A4F) with small-angle X-ray scattering (SAXS) for the detection of nanoparticles. The A4F was used to fractionate superparamagnetic maghemite nanoparticles, which were prepared continuously with a micromixer. The outlet of the A4F was directly coupled to a flow capillary of a SAXSess instrument (Kratky type of camera). SAXS curves were recorded in a 1 s time interval. This was possible by using intense synchrotron radiation. The radii of gyration of the nanoparticles, as determined from Guinier plots, increased from 2 to 6 nm with increasing fractionation time of the A4F. A more detailed analysis of the scattering curves revealed that the particles were cylindrical in shape (nanorods), which we attributed to the micromixing preparation technique. The radii of the nanorods increased only slightly from 1.2 to 1.7 nm with increasing fractionation time, while the lengths increased strongly from 7.0 to 30.0 nm. The volume distribution of the nanorods was determined and described by Schultz-Zimm and log-normal distributions. Nanorod volumes increased from 45 to 263 nm³, corresponding to molar masses of 140 × 10³ to 820 × 10³ g mol-1. We propose A4F-SAXS coupling as a new method for analysis of nanoparticles of complex composition in solution. It allows precise online determination of the particle’s shape and size distributions. This method can be applied to mixtures of nanoparticles of arbitrary shapes and sizes (1-100 nm). Moreover, the total time needed for fractionation and online SAXS data recording is usually only 20 min. PY - 2008 DO - https://doi.org/10.1021/ac8004814 SN - 0003-2700 SN - 1520-6882 VL - 80 IS - 15 SP - 5905 EP - 5911 PB - American Chemical Society CY - Washington, DC AN - OPUS4-17813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leiterer, Jork A1 - Leitenberger, W. A1 - Emmerling, Franziska A1 - Thünemann, Andreas A1 - Panne, Ulrich T1 - The use of an acoustic levitator to follow crystallization in small droplets by energy-dispersive X-ray diffraction N2 - For the investigation of small sample volumes, the use of an acoustic levitator was tested as a `sample holder' for hovering droplets in a synchrotron beam. It might be advantageous to use levitated droplets instead of samples confined in solid holders, especially for the study of crystallization processes where the influence of containing walls has to be minimized. In a first experiment, the crystallization of sodium chloride in a small droplet of aqueous solution has been followed with a time resolution of 30 s. The collected diffraction peaks are compared with data in the ICSD database. KW - EDXD KW - Noncontact measurement technique KW - X-ray-scattering KW - Synchrotron-radiation KW - Acoustic levitation PY - 2006 DO - https://doi.org/10.1107/S0021889806024915 SN - 0021-8898 SN - 1600-5767 VL - 39 IS - 5 SP - 771 EP - 773 PB - Blackwell CY - Oxford AN - OPUS4-13516 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Developtment of Nanoplastics Reference Materials at BAM N2 - Engineered particles are essential for sustainable innovation and modern industrial applications, but their reliable, number‑based characterisation remains a major challenge. Regulatory frameworks in healthcare, personal care (EU 745/2017, 749/2017, 1223/2009), and environmental monitoring—such as the EU Drinking Water Directive 21840/2020—demand robust particle measurements across complex matrices. Yet standardised methods currently exist only for simple particle systems, leaving significant gaps for technologically relevant materials and for micro‑ and nanoplastics as emerging pollutants. These challenges are amplified by the lack of well‑defined input parameters, particularly density and refractive index, which are critical for many analytical and modelling approaches. This talk highlights BAM’s work on developing nanoplastics reference materials to support validated, traceable, and harmonised measurement methods. I will outline strategies for producing stable, well‑characterised polymeric nanoparticles, establishing accurate material parameters, and integrating these reference materials into interlaboratory and standardisation activities. These efforts provide the metrological foundation urgently needed for regulatory testing, environmental monitoring, and industry innovation. T2 - ConcenSus Virtual Webinar on Reference Materials supporting characterization of nanomaterials: Current status and future trends CY - Online meeting DA - 17.03.2026 KW - Nanoplastics KW - Nanoparticle PY - 2026 AN - OPUS4-65717 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leiterer, Jork A1 - Panne, Ulrich A1 - Thünemann, Andreas A1 - Weidner, Steffen T1 - Container-less polymerization in acoustically levitated droplets: an analytical study by GPC and MALDI-TOF mass spectrometry N2 - Molecular masses and end groups of polystyrene (PS) formed in a novel container-less polymerization strategy, based on levitated droplets in an acoustic trap, were determined by Gel Permeation Chromatography (GPC) and Matrix-assisted Laser Desorption/Ionization Time of Flight Mass spectrometry (MALDI-TOF MS). KW - Ultraschallfalle KW - MALDI Massenspektrometrie KW - Polymerisation PY - 2011 DO - https://doi.org/10.1039/c0ay00390e SN - 1759-9660 SN - 1759-9679 VL - 3 IS - 1 SP - 70 EP - 73 PB - RSC Publ. CY - Cambridge AN - OPUS4-23655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Polte, Jörg A1 - Herder, Martin A1 - Erler, Robert A1 - Rolf, Simone A1 - Fischer, A. A1 - Würth, Christian A1 - Thünemann, Andreas A1 - Kraehnert, R. A1 - Emmerling, Franziska T1 - Mechanistic insights into seeded growth processes of gold nanoparticles N2 - A facile approach for the synthesis of monodisperse gold nanoparticles with radii in the range of 7 to 20 nm is presented. Starting from monodisperse seeds with radii of 7 nm, produced in the first step, the addition of a defined amount of additional precursor material permits distinct size regulation and the realization of predicted nanoparticle sizes. These information were derived from ex- and in situ investigations by comprehensive small angle X-ray scattering (SAXS), X-ray absorption near edge structure (XANES) and UV-Vis data to obtain information on the physicochemical mechanisms. The obtained mechanisms can be transferred to other seeded growth processes. Compared to similar approaches, the presented synthesis route circumvents the use of different reducing or stabilizing agents. The size of resulting nanoparticles can be varied over a large size range presented for the first time without a measurable change in the shape, polydispersity or surface chemistry. Thus, the resulting nanoparticles are ideal candidates for size dependence investigations. KW - Gold nanoparticles KW - SAXS KW - XANES KW - Growth mechanism PY - 2010 DO - https://doi.org/10.1039/c0nr00541j SN - 2040-3364 SN - 2040-3372 VL - 2 IS - 11 SP - 2463 EP - 2469 PB - RSC Publ. CY - Cambridge AN - OPUS4-22346 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 - 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 - 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 - CONF A1 - Sieg, Holger A1 - Heilscher, Jasmin A1 - Ott, Franziska A1 - Böhmert, Linda A1 - Drusch, Stephan A1 - Thünemann, Andreas A1 - Rohn, Sascha A1 - Braeuning, Albert A1 - Kieserling, Helena T1 - Direct Interactions of Micro- and Nanoplastics with Proteins – A Key to Mechanistic Understanding? N2 - Micro-/Nanoplastics (MNP) have gained widespread scientific and public attention within the last two decades. While knowledge about measuring techniques, occurrence and exposure was improved substantially, questions on toxicological impact of MNP remained unclear. A major reason for that are the continued remaining knowledge gaps with regard to mechanistical understanding of MNP effects. Our work aimed at investigating MNP properties, protein interactions, and cellular effects in combination. Therefore, we characterized MNP-protein- adsorption, changes in protein structure, cellular uptake and cellular modes of action. In a first study, we studied the molecular interactions of β-lactoglobulin, a serum and storage protein, with different MNP materials1. We identified structural changes, depending on physicochemical MNP properties, using FTIR- and fluorescence spectroscopy. Furthermore, we investigated cellular uptake of MNP individually and as a complex with β-lactoglobulin and studied the effects on cell growth and viability, using colorimetric MTT testing, flow cytometry, and cell impedance measurements. MNP material properties, especially hydrophobicity, had an impact on protein folding and consequently also on cellular interactions. In a second study, we applied α-amylase, an extracellular digestive protein with enzymatic activity. Here, in addition, we investigated the influence of MNP binding on enzyme activity, using a colorimetric starch degradation assay. We observed for the most MNP, that adsorption processes resulted in a decrease of enzyme activity. Furthermore, we used Alexa633 staining to visualize MNP uptake with and without the presence of α-amylase. Taken together, this work aims to close data gaps regarding mechanistical effects of MNP on cells by investigating direct MNP-protein-interactions. Mechanistic knowledge is crucial for understanding toxicological effects of MNP, and therefore, also for the risk assessment of possible hazards on human health. T2 - 92. Jahrestagung der Deutschen Gesellschaft für Experimentelle und Klinische Pharmakologie und Toxikologie (DGPT) CY - Düsseldorf, Germany DA - 17.03.2026 KW - Microplastics KW - Nanoplastics PY - 2026 AN - OPUS4-65667 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fandrich, Nick A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Staal, B. A1 - Thünemann, Andreas A1 - Laschewsky, A. T1 - Characterization of new amphiphilic block copolymers of N-vinylpyrrolidone and vinyl acetate, 2 - chromatographic separation and analysis by MALDI-TOF and FT-IR coupling N2 - PVP-block-PVAc block copolymers were synthesized by controlled radical polymerization applying a RAFT/MADIX system and were investigated by HPLC and by coupling of chromatography to FT-IR spectroscopy and MALDI-TOF MS. Chromatographic methods (LACCC and gradient techniques) were developed that allowed a separation of block copolymers according to their repeating units. The results of the spectroscopic and spectrometric analysis clearly showed transfer between radicals and process solvent. With the use of hyphenated techniques differences between main and side products were detected. In agreement with previously published results, obtained by NMR, SEC, static light scattering and MALDI-TOF MS, our data proved a non-ideal RAFT polymerization. KW - Amphiphiles KW - Block copolymers KW - Liquid chromatography KW - MALDI KW - Reversible addition fragmentation chain transfer (RAFT) KW - Liquid adsorption chromatography at critical conditions KW - Gradient chromatography KW - MALDI-TOF mass spectrometry KW - Hyphenated techniques KW - Mechanism of polymerization PY - 2010 DO - https://doi.org/10.1002/macp.201000044 SN - 1022-1352 SN - 1521-3935 VL - 211 IS - 15 SP - 1678 EP - 1688 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-22012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böhmert, L. A1 - Girod, Matthias A1 - Hansen, Ulf A1 - Maul, Ronald A1 - Knappe, Patrick A1 - Niemann, B. A1 - Weidner, Steffen A1 - Thünemann, Andreas A1 - Lampen, A. T1 - Analytically monitored digestion of silver nanoparticles and their toxicity on human intestinal cells N2 - Orally ingested nanoparticles may overcome the gastrointestinal barrier, reach the circulatory system, be distributed in the organism and cause adverse health effects. However, ingested nanoparticles have to pass through different physicochemical environments, which may alter their properties before they reach the intestinal cells. In this study, silver nanoparticles are characterised physicochemically during the course of artificial digestion to simulate the biochemical processes occurring during digestion. Their cytotoxicity on intestinal cells was investigated using the Caco-2 cell model. Using field-flow fractionation combined with dynamic light scattering and small-angle X-ray scattering, the authors found that particles only partially aggregate as a result of the digestive process. Cell viabilities were determined by means of CellTiter-Blue® assay, 4',6-diamidino-2-phenylindole-staining and real-time impedance. These measurements reveal small differences between digested and undigested particles (1–100 µg/ml or 1–69 particles/cell). The findings suggest that silver nanoparticles may indeed overcome the gastrointestinal juices in their particulate form without forming large quantities of aggregates. Consequently, the authors presume that the particles can reach the intestinal epithelial cells after ingestion with only a slight reduction in their cytotoxic potential. The study indicates that it is important to determine the impact of body fluids on the nanoparticles of interest to provide a reliable interpretation of their nano-specific cytotoxicity testing in vivo and in vitro. KW - Silver nanoparticles KW - In vitro digestion KW - Field-flow fractionation KW - Small-angle X-ray scattering KW - Dynamic light scattering KW - Caco-2 cells PY - 2014 DO - https://doi.org/10.3109/17435390.2013.815284 SN - 1743-5390 SN - 1743-5404 VL - 8 IS - 6 SP - 631 EP - 642 PB - Informa Healthcare CY - London AN - OPUS4-29926 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Knop, K. A1 - Thünemann, Andreas T1 - Structure and end-group analysis of complex hexanediol-neopentylglycol-adipic acid copolyesters by matrix-assisted laser desorption/ionization collision-induced dissociation tandem mass spectrometry N2 - Sequences and end groups of complex copolyesters were determined by fragmentation analysis by means of matrix-assisted laser desorption/ionization collision-induced dissociation tandem mass spectrometry (MALDI CID MS/MS). The complexity of the crude copolyester mixture was reduced by a chromatographic separation followed by a MALDI time-of-flight (TOF) investigation of fractions. Due to overlapping compositional and end-group information a clear assignment of end groups was very difficult. However, the fragmentation of suitable precursor ions resulted in typical fragment ion patterns and, therefore, enabled a fast and unambiguous determination of the end groups and composition of this important class of polymers. KW - Fragmentierung KW - MALDI Massenspektrometrie KW - Polymere KW - MS/MS PY - 2009 DO - https://doi.org/10.1002/rcm.4191 SN - 0951-4198 SN - 1097-0231 VL - 23 IS - 17 SP - 2768 EP - 2774 PB - Wiley CY - Chichester AN - OPUS4-20929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - In Situ Characterization of Superparamagnetic Nanoparticles: Online Coupling of FFF and SAXS using Synchrotron Radiation T2 - Workshop on structural aspects of biocompatible ferrofluids: stabilization, properties control and application CY - Geesthacht, Germany DA - 2010-01-28 PY - 2010 AN - OPUS4-20100 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fandrich, Nick A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Pfeifer, Dietmar A1 - Staal, B. A1 - Thünemann, Andreas A1 - Laschewsky, A. T1 - Characterization of new amphiphilic block copolymers of N-vinyl pyrrolidone and vinyl acetate, 1 - analysis of copolymer composition, end groups, molar masses and molar mass distributions N2 - New amphiphilic block copolymers consisting of N-vinyl pyrrolidone and vinyl acetate were synthesized via controlled radical polymerization using a reversible addition/fragmentation chain transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) system. The synthesis was carried out in 1,4-dioxane as process solvent. In order to get conclusions on the mechanism of the polymerization the molecular structure of formed copolymers was analysed by means of different analytical techniques. 13C NMR spectroscopy was used for the determination of the monomer ratios. End groups were analysed by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This technique was also used to determine possible fragmentations of the RAFT end groups. By means of a combination of size exclusion chromatography, 13C NMR and static light scattering molar mass distributions and absolute molar masses could be analysed. The results clearly show a non-ideal RAFT mechanism. KW - Amphiphiles KW - Block copolymers KW - Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) KW - N-vinyl pyrrolidone KW - Reversible addition/fragmentation chain transfer (RAFT) PY - 2010 DO - https://doi.org/10.1002/macp.200900466 SN - 1022-1352 SN - 1521-3935 VL - 211 IS - 8 SP - 869 EP - 878 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-21905 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Knappe, Patrick A1 - Bienert, Ralf A1 - Weidner, Steffen A1 - Thünemann, Andreas T1 - Characterization of poly/N-vinyl-2-pyrrolidone)s with broad size distributions N2 - We report on the characterization of the solution structure of poly(N-vinyl-2-pyrrolidone)s (PVP) by small-angle X-ray scattering (SAXS) and by online coupling of asymmetrical flow field-flow fractionation (A4F), SAXS and dynamic light scattering (DLS). The commercial products PVP K30 and PVP K90 with nominal molar masses of 40 × 103 and 360 × 103 g mol-1, respectively, were investigated separately and as binary mixture. Detailed information for all polymer fractions is available on the polymer contour lengths and the diffusion coefficients. Key areas of applications for the A4F-SAXS-DLS coupling are seen in comparison to static light scattering for polymers with radii of gyration smaller than 10 nm, for which only SAXS produces precise analytical results on the size of the polymers in solution. KW - Small-angle X-ray scattering KW - SAXS KW - Field-flow fractionation PY - 2010 DO - https://doi.org/10.1016/j.polymer.2010.02.039 SN - 0032-3861 SN - 1873-2291 VL - 51 IS - 8 SP - 1723 EP - 1727 PB - Springer CY - Berlin AN - OPUS4-21222 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - An X-ray view into the nano-world T2 - Workshop "Trends in Colloid and Interface Science TICI" CY - Potsdam, Germany DA - 2011-06-22 PY - 2011 AN - OPUS4-23978 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thünemann, Andreas A1 - Knappe, Patrick A1 - Bienert, Ralf A1 - Weidner, Steffen T1 - Online coupling of field-flow fractionation with SAXS and DLS for polymer analysis N2 - We report on a hyphenated polymer analysis method consisting of asymmetrical flow field-flow fractionation (A4F) coupled online with small-angle X-ray scattering (SAXS) and dynamic light scattering (DLS). A mixture of six poly(styrene sulfonate)s with molar masses in the range of 6.5 × 103 to 1.0 × 106 g mol-1 was used as a model system for polyelectrolytes in aqueous solutions with a broad molar mass distribution. A complete polymer separation and analysis was performed in 60 min. Detailed information for all polymer fractions are available on i) the radii of gyration, which were determined from the SAXS data interpretation in terms of the Debye model (Gaussian chains), and ii) the diffusion coefficients (from DLS). We recommend using the A4F-SAXS-DLS coupling as a possible new reference method for the detailed analysis of complex polymer mixtures. Advantages of the use of SAXS are seen in comparison to static light scattering for polymers with radii of gyration smaller then 15 nm, for which only SAXS produces precise analytical results on the size of the polymers in solution. PY - 2009 DO - https://doi.org/10.1039/b9ay00107g SN - 1759-9660 SN - 1759-9679 VL - 1 SP - 177 EP - 182 PB - RSC Publ. CY - Cambridge AN - OPUS4-20567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - El Malah, T. A1 - Rolf, Simone A1 - Weidner, Steffen A1 - Thünemann, Andreas A1 - Hecht, S. T1 - Amphiphilic folded dendrimer discs and their thermosensitive self-assembly in water N2 - Folded dendrimers with peripheral ether side chains show a thermally induced hierarchical aggregation process, in which the transition temperature and the dimensions of the aggregates can readily be tuned via the generation number (see figure). KW - Click chemistry KW - Cotton effect KW - Dendrimers KW - Hierarchical self-assembly KW - Thermochemistry PY - 2012 DO - https://doi.org/10.1002/chem.201200414 SN - 0947-6539 SN - 1521-3765 VL - 18 IS - 19 SP - 5837 EP - 5842 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-25822 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thünemann, Andreas A1 - Rolf, Simone A1 - Knappe, Patrick A1 - Weidner, Steffen T1 - In Situ Analysis of a Bimodal Size Distribution of Superparamagnetic Nanoparticles N2 - The dispersed iron oxide nanoparticles of ferrofluids in aqueous solution are difficult to characterize due to their protective polymer coatings. We report on the bimodal size distribution of superparamagnetic iron oxide nanoparticles found in the MRI contrast agent Resovist, which is a representative example of commercial nanoparticle-based pharmaceutical formulations. The radii of the majority of the nanoparticles (>99%) range from 4 to 13 nm (less than 1% of the particles display radii up to 21 nm). The maxima of the size distributions are at 5.0 and 9.9 nm. The analysis was performed with in situ characterization of Resovist via online coupling of asymmetrical flow field-flow fractionation (A4F) with small-angle X-ray scattering (SAXS) using a standard copper X-ray tube as a radiation source. The outlet of the A4F was directly coupled to a flow capillary on the SAXS instrument. SAXS curves of nanoparticle fractions were recorded at 1-min time intervals. We recommend using the A4F-SAXS coupling as a routine method for analysis of dispersed nanoparticles with sizes in the range of 1-100 nm. It allows a fast and quantitative comparison of different batches without the need for sample preparation. PY - 2009 DO - https://doi.org/10.1021/ac802009q SN - 0003-2700 SN - 1520-6882 VL - 81 IS - 1 SP - 296 EP - 301 PB - American Chemical Society CY - Washington, DC AN - OPUS4-18658 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - In Situ Analysis of Size Distributions of Polymer-Stabilized Nanoparticles T2 - 8th International Conference on Advanced Polymers via Macromolecular Engineering CY - Dresden, Germany DA - 2009-10-04 PY - 2009 AN - OPUS4-19417 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Knappe, Patrick A1 - Bienert, Ralf A1 - Weidner, Steffen A1 - Thünemann, Andreas T1 - Poly(acrylic acid): A combined analysis with field-flow fractionation and SAXS N2 - Polyelectrolytes such as PAA and its salts are widely used, but are notoriously difficult to characterize due to their polyelectrolyte properties and broad molecular mass distributions. In this paper, we report on a new PAA analysis by combining asymmetrical flow field-flow fractionation and an advanced SAXS technique using an acoustic levitator to minimize background scattering. The proof-of-principle is demonstrated with a mixture of three standard PAAs with different molecular masses. Detailed information on the PAA fractions is available on radii of gyration, polymer contour lengths, and coil conformation. Our method is expected to be applicable for a wide range of water-soluble synthetic and natural polymers and ideal for molecular masses of 5 × 103–2 × 105 g · mol-1. KW - Fractionation of polymers KW - Molar mass distribution KW - Polyelectrolytes KW - Small-angle X-ray scattering KW - Water-soluble polymers PY - 2010 DO - https://doi.org/10.1002/macp.201000163 SN - 1022-1352 SN - 1521-3935 VL - 211 IS - 19 SP - 2148 EP - 2153 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-22005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - Characterization of Polymers and Nanoparticles by Online Coupling of Field-Flow Fractionation with SAXS and other Detection Principles T2 - Vortrag auf Kolloquium des Instituts für Wasserchemie und Chemische Balneologie der Technischen Universität München CY - Munich, Germany DA - 2009-11-09 PY - 2009 AN - OPUS4-20101 LA - deu 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 -