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] (LH