1. BG Universitätsklinikum Bergmannsheil/Surgical Research, Ruhr-University Bochum, Bürkle-de-la-Camp-Platz 1, 44789 Bochum, Germany
2. Chair of Biomaterials and Polymer Science, Department of Biochemical and Chemical Engineering, TU Dortmund, Emil-Figge-Str. 66, 44227 Dortmund, Germany