1. Biosensor Technologies, AIT-Austrian Institute of Technology GmbH, Konrad-Lorenz-Straße 24, Tulln an der Donau 3430, Austria
2. CEST Competence Center for Electrochemical Surface Technologies, Tulln an der Donau 3430, Austria
3. Czech Academy of Sciences, FZU-Institute of Physics, Na Slovance 2, Prague 182 21, Czech Republic
4. Macromolecular Chemistry, Department Chemistry-Biology, University of Siegen, Siegen 57076, Germany