1. Division of Biophysics and Bioengineering, IFM, Linköping University, SE-581 83 Linköping, Sweden
2. Division of Molecular Surface Physics and Nanoscience, IFM, Linköping University, SE-581 83 Linköping, Sweden
3. Leibniz Institute of Polymer Research Dresden, Max Bergmann Center of Biomaterials Dresden, Hohe Strasse 6, 01069 Dresden, Germany
4. Centre for Biomimetic Sensor Science, School of Materials Science and Engineering, Nanyang Technological University, Singapore 637553