1. Biointerface Laboratory, RWTH Aachen University Hospital, Aachen, Germany.
2. Department of Dental Materials and Biomaterial Research, RWTH Aachen University Hospital, Aachen, Germany.
3. Institute of Pathology, RWTH Aachen University Hospital, Aachen, Germany.
4. Experimental Molecular Imaging, Helmholtz Institute of Biomedical Engineering, RWTH Aachen University Hospital, Aachen, Germany.