1. BiointerfaceGroup, Laboratory for Surface Science and Technology, Department of Materials, Swiss Federal Institute of Technology (ETH) Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland, Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology (ETH) Zurich, Schafmattstrasse 20, CH-8093 Zurich, Switzerland, and Institute for Biomedical Engineering, Swiss Federal Institute of Technology (ETH) and University of Zurich, Moussonstrasse 18, CH-8044 Zurich, Switzerland