1. Institute of Pathology, RWTH Aachen University, Aachen, Germany.
2. Stem Cell Biology and Cellular Engineering Group, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany.
3. Biointerface Group, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany.
4. Electron Microscopic Facility, University Hospital Aachen, Aachen, Germany.
5. Department for Gynecology, RWTH Aachen University, Aachen, Germany.
6. Department of Cell Biology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany.
7. Institute for Medical Radiation and Cell Research, University of Würzburg, Würzburg, Germany.