1. Institute of Biomaterial Science, Berlin-Brandenburg Center for Regenerative Therapies; Helmholtz-Zentrum Geesthacht; Kantstr. 55 14513 Teltow Germany
2. Institute of Chemistry; University of Potsdam; Karl-Liebknecht-Str. 24-25 14476 Potsdam Germany
3. Helmholtz Virtual Institute-Multifunctional Biomaterials for Medicine; Kantstr. 55 14513 Teltow Germany
4. Institute of Chemistry and Biochemistry; Freie Universität Berlin; Takustr. 3 14195 Berlin Germany