@article{DraudeKoersgenPelsteretal.2015,
  author    = {Draude, Felix and K{\"o}rsgen, Martin and Pelster, Andreas and Schwerdtle, Tanja and M{\"u}thing, Johannes and Arlinghaus, Heinrich F.},
  title     = {Characterization of freeze-fractured epithelial plasma membranes on nanometer scale with ToF-SIMS},
  series = {Analytical \& bioanalytical chemistry},
  volume    = {407},
  journal   = {Analytical \& bioanalytical chemistry},
  number    = {8},
  publisher = {Springer},
  address   = {Heidelberg},
  issn      = {1618-2642},
  doi       = {10.1007/s00216-014-8334-2},
  pages     = {2203 -- 2211},
  year      = {2015},
  abstract  = {Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to characterize the freeze-fracturing process of human epithelial PANC-1 and UROtsa cells. For this purpose, phosphatidylcholine, sphingomyelin, phosphatidylethanolamine, and phosphatidylserine standard samples were investigated to find specific signals with both high specificity and signal intensity. The results were used to investigate single cells of subconfluent cell layers prepared with a special silicon wafer sandwich preparation technique. This freeze-fracturing technique strips cell membranes off the cells, isolating them on opposing silicon wafer substrates. Criteria were found for defining regions with stripped off cell membranes and, on the opposing wafer, complementary regions with the remaining cells. Measured ethanolamine/choline and serine/choline ratios in these regions clearly showed that in the freeze-fracturing process, the lipid bilayer of the plasma membrane is split along its central zone. Accordingly, only the outer lipid monolayer is stripped off the cell, while the inner lipid monolayer remains attached to the cell on the opposing wafer, thus allowing detailed analysis of a single lipid monolayer. Furthermore, it could be shown that using different washing procedures did not influence the transmembrane lipid distribution. Under optimized preparation conditions, it became feasible to detect lipids with a lateral resolution of approximately 100 nm. The data indicate that ToF-SIMS would be a very useful technique to study with very high lateral resolution changes in lipid composition caused, for example, by lipid storage diseases or pharmaceuticals that interfere with the lipid metabolism.},
  language  = {en}
}
@article{HaaseArlinghausTentschertetal.2011,
  author    = {Haase, Andrea and Arlinghaus, Heinrich F. and Tentschert, Jutta and Jungnickel, Harald and Graf, Philipp and Mantion, Alexandre and Draude, Felix and Galla, Sebastian and Plendl, Johanna and Goetz, Mario E. and Masic, Admir and Meier, Wolfgang P. and Thuenemann, Andreas F. and Taubert, Andreas and Luch, Andreas},
  title     = {Application of Laser Postionization Secondary Neutral Mass Spectrometry/Time-of-Flight Secondary Ion Mass Spectrometry in Nanotoxicology: Visualization of Nanosilver in Human Macrophages and Cellular Responses},
  series = {ACS nano},
  volume    = {5},
  journal   = {ACS nano},
  number    = {4},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1936-0851},
  doi       = {10.1021/nn200163w},
  pages     = {3059 -- 3068},
  year      = {2011},
  abstract  = {Silver nanoparticles (SNP) are the subject of worldwide commercialization because of their antimicrobial effects. Yet only little data on their mode of action exist. Further, only few techniques allow for visualization and quantification of unlabeled nanoparticles inside cells. To study SNP of different sizes and coatings within human macrophages, we introduce a novel laser postionization secondary neutral mass spectrometry (Laser-SNMS) approach and prove this method superior to the widely applied confocal Raman and transmission electron microscopy. With time-of-flight secondary ion mass spectrometry (TOF-SIMS) we further demonstrate characteristic fingerprints in the lipid pattern of the cellular membrane indicative of oxidative stress and membrane fluidity changes. Increases of protein carbonyl and heme oxygenase-1 levels in treated cells confirm the presence of oxidative stress biochemically. Intriguingly, affected phagocytosis reveals as highly sensitive end point of SNP-mediated adversity In macrophages. The cellular responses monitored are. hierarchically linked, but follow individual kinetics and are partially reversible.},
  language  = {en}
}