1. Physics Department (E14), TU Munich, 85748 Garching, Germany.
2. Center for NanoScience (CeNS), Schellingstraße 4, 80799 Munich, Germany.
3. Center for Applied Tissue Engineering and Regenerative Medicine-CANTER, Munich University of Applied Sciences, Lothstrasse 34, 80335 Munich, Germany.
4. Heinz-Nixdorf-Chair of Biomedical Electronics, TranslaTUM, TU Munich, 81675 Munich, Germany.