1. Department of Materials, ETH-Zürich, Leopold-Ruzicka-Weg 4, 8093 Zürich, Switzerland
2. xirrus GmbH, Buchzelgstrasse 36, 8053 Zürich, Switzerland
3. Department of Biology and Chemistry, Paul Scherrer Institute and Department of Biology, ETH-Zürich, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland