TY  - JOUR
A1  - Draude, F.
A1  - Pelster, A.
A1  - Koersgen, M.
A1  - Kassenboehmer, R.
A1  - Schwerdtle, Tanja
A1  - Muething, J.
A1  - Arlinghaus, H. F.
T1  - ToF-SIMS imaging of plasma membrane lipids with sub-micrometer resolution
JF  - Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films
N2  - 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.
KW  - ToF-SIMS
KW  - high-resolution imaging
KW  - membrane analysis
KW  - lipid analysis
KW  - yield enhancement
KW  - sample preparation
Y1  - 2014
U6  - https://doi.org/10.1002/sia.5576
SN  - 0142-2421
SN  - 1096-9918
VL  - 46
SP  - 127
EP  - 130
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Tentschert, Jutta
A1  - Jungnickel, Harald
A1  - Reichardt, Philipp
A1  - Leube, Peter
A1  - Kretzschmar, Bernd
A1  - Taubert, Andreas
A1  - Luch, A.
T1  - Identification of nano clay in composite polymers
JF  - Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films
N2  - 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.
KW  - ToF-SIMS
KW  - nanoparticles
KW  - nano clay
KW  - polymer
KW  - food contact material
Y1  - 2014
U6  - https://doi.org/10.1002/sia.5546
SN  - 0142-2421
SN  - 1096-9918
VL  - 46
SP  - 334
EP  - 336
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -