1. Department of Soft Matter Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands, Soft Matter cryoTEM Research Unit, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, and Van’t Hoff Laboratory, Debye Research Institute, Utrecht University, N-701 Padualaan 8, 3584 CH Utrecht, The Netherlands