1. G.E.R.N. Center for Tissue Replacement, Regeneration & Neogenesis, Department of Orthopedics and Trauma Surgery, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Engesserstraße 4, 79108 Freiburg, Germany
2. Faculty of Biology, University of Freiburg, Schaenzlestrasse 1, 79104 Freiburg, Germany