[1] Univ Potsdam, Inst Phys & Astron, D-14476 Potsdam, Germany
[2] Helmholtz Zentrum Geesthacht, Polymer Res Inst, Ctr Biomat Dev, Teltow, Germany
[3] Helmholtz Zentrum Geesthacht, Polymer Res Inst, Berlin Brandenburg Ctr Regenerat Therapies, Teltow, Germany