TY - JOUR A1 - López-Serrano Oliver, Ana A1 - Baumgart, S. A1 - Bremser, Wolfram A1 - Flemig, Sabine A1 - Wittke, D. A1 - Grützkau, A. A1 - Luch, A. A1 - Haase, A. A1 - Jakubowski, Norbert T1 - Quantification of silver nanoparticles taken up by single cells using inductively coupled plasma mass spectrometry in the single cell measurement mode N2 - The impact of nanoparticles, NPs, at the single cell level has become a major field of toxicological research and different analytical methodologies are being investigated to obtain biological and toxicological information to better understand the mechanisms of cell–NP interactions. Here, inductively coupled plasma mass spectrometry in the single cell measurement mode (SC-ICP-MS) is proposed to study the uptake of silver NPs, AgNPs, with a diameter of 50 nm by human THP-1 monocytes in a proof-ofprinciple experiment. The main operating parameters of SC-ICP-MS have been optimized and applied for subsequent quantitative analysis of AgNPs to determine the number of particles in individual cells using AgNP suspensions for calibration. THP-1 cells were incubated with AgNP suspensions with concentrations of 0.1 and 1 µg/mL for 4 and 24 hours. The results reveal that the AgNP uptake by THP-1 monocytes is minimal at the lower dose of 0.1 µg/mL (roughly 1 AgNP per cell was determined), whereas a large cell-to-cell variance dependent on the exposure time is observed for a 10 times higher concentration (roughly 7 AgNPs per cell). The method was further applied to monitor the AgNP uptake by THP-1 cells differentiated macrophages incubated at the same AgNP concentration levels and exposure times demonstrating a much higher AgNP uptake (roughly from 9 to 45 AgNPs per cell) that was dependent on exposure concentration and remained constant over time. The results have been compared and validated by sample digestion followed by ICP-MS analysis as well as with other alternative promising techniques providing single cell analysis. KW - Silbernanopartikel KW - ICP-MS KW - Einzelzellanalyse PY - 2018 U6 - https://doi.org/10.1039/C7JA00395A SN - 0267-9477 VL - 33 IS - 7 SP - 1256 EP - 1263 PB - Royal Society of Chemistry CY - London AN - OPUS4-45473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mohsin, G. F. A1 - Schmitt, F.-J. A1 - Kanzler, C. A1 - Epping, J. D. A1 - Flemig, Sabine A1 - Hornemann, A. T1 - Structural characterization of melanoidin formed from D-glucose and L-alanine at different temperatures applying FTIR, NMR, EPR, and MALDI-ToF-MS N2 - The aim of this study was to identify specific chemical bonds and characteristic structures in melanoidins formed from D-glucose and L-alanine between 130 and 200 °C. The results might be used to control the type and amount of melanoidin produced during food processing. For this purpose, complementary techniques, such as FTIR, NMR, EPR, and MALDI-ToF, were employed. At 160 °C color, solubility and UV/Vis absorption change characteristically and consequently, structural transformations could be observed in FTIR and NMR spectra. For example, sharp signals of N-H, C-N, and C-H oscillations in the L-alanine spectrum are prone to inhomogeneous broadening in melanoidins prepared above 150 °C. These changes are caused due to formation of heterogeneous macromolecular structures and occur during condensation reactions that lead to an increasing loss of water from the melanoidins with increasing temperatures. Additionally, MALDI-ToF-MS indicates the polymerization of glyoxal/glyoxylic acid and EPR shows the formation of radical structures. KW - MALDI-ToF-MS KW - Melanoidine KW - Konjugate KW - Lebensmittel KW - MALDI-ToF-MS KW - L-alanine KW - D-glucose KW - Maillard reaction KW - FTIR spectroscopy KW - EPR spectroscopy KW - Melanoidin KW - NMR spectroscopy PY - 2018 U6 - https://doi.org/10.1016/j.foodchem.2017.11.115 SN - 0308-8146 VL - 245 SP - 761 EP - 767 PB - Elsevier Science CY - Amsterdam, NL AN - OPUS4-44018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -