1. Department of Plastic and Hand Surgery, University of Erlangen Medical Center, Erlangen, Germany.
2. Department of Materials Science and Engineering, Institute for Biomaterials, University of Erlangen-Nuremberg, Erlangen, Germany.
3. Department of Materials, Imperial College London, London, United Kingdom.
4. Department of Materials Science and Engineering, Institute of Glass and Ceramics, University of Erlangen-Nuremberg, Erlangen, Germany.