1. Adolphe Merkle Institute University of Fribourg Chemin des Verdiers 4 1700 Fribourg Switzerland
2. Current address: Department of Materials and Department of Bioengineering Institute of Biomedical Engineering Imperial College London Exhibition Road London SW7 2AZ UK
3. Department of Pure and Applied Chemistry University of Strathclyde Thomas Graham Building, 295 Cathedral Street Glasgow G1 1XL UK
4. BioEM lab Center of Cellular Imaging and NanoAnalytics (C-CINA) Biozentrum University of Basel Mattenstrasse 26 4058 Basel Switzerland
5. Soft Materials Laboratory Institute of Materials École Polytechnique Fédérale de Lausanne, EPFL-STI-IMX-SMAL MXC 231 Station 12 1015 Lausanne Switzerland
6. Department of Chemistry University of Fribourg Chemin du Musée 9 1700 Fribourg Switzerland