1. Wyss Institute for Biologically Inspired Engineering; Harvard University; Boston MA 02115 USA
2. John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge MA 02138 USA
3. Harvard-MIT Division of Health Sciences and Technology; Cambridge MA 02139 USA
4. Julius Wolff Institute and Center for Musculoskeletal Surgery; Charité - Universitätsmedizin Berlin; 13353 Germany