1. Department of Biomaterials; Radboud Institute for Molecular Life Sciences; Radboud University Medical Center; Philips van Leydenlaan 25 6525 EX Nijmegen The Netherlands
2. Department of Solid State NMR; Institute for Molecules and Materials; Radboud University; Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands
3. Biophysical Chemistry Group; Institute of Biochemistry; Faculty of Biosciences; Pharmacy and Psychology; Universität Leipzig; D-04103 Leipzig Germany
4. Institute of Organic and Macromolecular Chemistry; Heinrich-Heine-University Düsseldorf; Universitätsstrasse 1 D-40225 Düsseldorf Germany
5. Department of Biomaterials; Max Planck Institute for Colloids and Interfaces; D-14424 Potsdam Germany