1. Institute for Experimental Molecular Imaging, RWTH Aachen University Hospital, 52074 Aachen, Germany
2. DWI − Leibniz Institute for Interactive Materials, 52074 Aachen, Germany
3. Institute for Technical and Macromolecular Chemistry, RWTH Aachen University, 52074 Aachen, Germany
4. Institute of Applied Medical Engineering, Department of Advanced Materials for Biomedicine, RWTH Aachen University, 52074 Aachen, Germany
5. Electron Microscope Facility, RWTH Aachen University Hospital, 52074 Aachen, Germany