1. BioEM Facility, Centre Interdisciplinaire de Microscopie Electronique, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
2. Friedrich Miescher Institute for BioMedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland and Center for Cellular Imaging and NanoAnalytics, BioZentrum, University of Basel, 4058 Basel, Switzerland