1. Nanoparticle Systems Engineering Lab, ETH Zurich, Sonneggstrasse 3, 8092 Zurich, Switzerland
2. Laboratory for Particles-Biology Interactions, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
3. Department of Chemistry, Bochum University, Universitätsstrasse 150, 44801 Bochum, Germany
4. Fraunhofer Institute of Microelectronic Circuits and Systems, Finkenstrasse 61, 47057 Duisburg, Germany