@article{DraudePelsterKoersgenetal.2014, author = {Draude, F. and Pelster, A. and Koersgen, M. and Kassenboehmer, R. and Schwerdtle, Tanja and Muething, J. and Arlinghaus, H. F.}, title = {ToF-SIMS imaging of plasma membrane lipids with sub-micrometer resolution}, series = {Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films}, volume = {46}, journal = {Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0142-2421}, doi = {10.1002/sia.5576}, pages = {127 -- 130}, year = {2014}, abstract = {Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used for label-free analyses of the molecular lateral distribution of two different epithelial cell membranes (PANC-1 and UROtsa). The goal of the research was to enhance the ion yield of specific membrane molecules for improving the membrane imaging capability of ToF-SIMS on the nanoscale lateral dimension. For this task, a special silicon wafer sandwich preparation technique was optimized using different wafer materials, spacers, and washing procedures. Under optimized preparation conditions, the yield could be significantly enhanced, allowing imaging of the inhomogeneous distribution of phosphocholine (common head group for phosphatidylcholine and sphingomyelin) of a PANC-1 cell membrane's outer lipid layer with a lateral resolution of less than 200nm. Copyright (c) 2014 John Wiley \& Sons, Ltd.}, language = {en} } @article{TentschertJungnickelReichardtetal.2014, author = {Tentschert, Jutta and Jungnickel, Harald and Reichardt, Philipp and Leube, Peter and Kretzschmar, Bernd and Taubert, Andreas and Luch, A.}, title = {Identification of nano clay in composite polymers}, series = {Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films}, volume = {46}, journal = {Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0142-2421}, doi = {10.1002/sia.5546}, pages = {334 -- 336}, year = {2014}, abstract = {Industrialized food production is in urgent search for alternative packaging materials, which can serve the requirements of a globalized world in terms of longer product shelf lives, reduced freight weight to decrease transport costs, and better barrier functionality to preserve its freshness. Polymer materials containing organically modified nano clay particles as additives are one example for a new generation of packaging materials with specific barrier functionality to actually hit the market. Clay types used for these applications are aluminosilicates, which belong to the mineral group of phyllosilicates. These consist of nano-scaled thin platelets, which are organically modified with quaternary ammonium compounds acting as spacers between the different clay layers, thereby increasing the hydrophobicity of the mineral additive. A variety of different organically modified clays are already available, and the use as additive for food packaging materials is one important application. To ensure valid risk assessments of emerging nano composite polymers used in the food packaging industry, exact analytical characterization of the organically modified clay within the polymer matrix is of paramount importance. Time-of-flight SIMS in combination with multivariate statistical analysis was used to differentiate modified clay reference materials from another. Time-of-flight SIMS spectra of a reference polymer plate, which contained one specific nano clay composite, were acquired. For each modified clay additive, a set of characteristic diagnostic ions could be identified, which then was used to successfully assign unknown clay additives to the corresponding reference material. Thus, the described methodology could be used to define and characterize nano clay within polymer matrices. Copyright (c) 2014 John Wiley \& Sons, Ltd.}, language = {en} }