1. Functional Materials, Institute of Materials Science, Technical University of Darmstadt, Peter-Grünberg-Str. 16, 64287 Darmstadt, Germany
2. Stem Cell and Developmental Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
3. Advanced Electron Microscopy Division, Institute of Materials Science, Technical University of Darmstadt, Peter-Grünberg-Str. 22, 64287 Darmstadt, Germany