1. Department of Polymer Chemistry; Zernike Institute for Advanced Materials; University of Groningen; Nijenborgh 4 9747 AG Groningen The Netherlands
2. University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering; Antonius Deusinglaan 1 9713 AV Groningen The Netherlands
3. Surfaces and Thin Films Group; Zernike Institute for Advanced Materials; University of Groningen; Nijenborgh 4 9747 AG Groningen The Netherlands
4. Biomaterials and Polymer Science; Department of Bio- and Chemical Engineering; TU Dortmund; Emil-Figge-Strasse 66 44227 Dortmund Germany