1. Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
2. Institute of Inorganic Chemistry, Essen, Germany
3. Centre for Nanointegration Duisburg-Essen (CeNIDE), Essen, Germany
4. Institute for Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany