1. Institute for Biomechanics, ETH Zurich, D-HEST, Vladimir-Prelog-Weg 3, 8093 Zurich, CH (Corresponding author), e-mail: nicole.ade@alumni.ethz.ch
2. Swiss Federal Laboratories for Materials Science and Technology (EMPA), Protection and Physiology, Lerchenfeldstrasse 5, 9014 St. Gallen, CH, e-mail: rolf.Staempfli@empa.ch
3. Schmitt Kai-Uwe, Institute for Biomedical Engineering, Univ. and ETH Zurich, Gloriastrasse 35, 8092 Zurich, CH, e-mail: schmitt@ethz.ch