1. Department of Biotechnology, University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland
2. Nano-Science Center, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
3. Department of Chemistry, Ludwig-Maximilians University of Munich, Butenandtstr. 5-13, 81377 Munich, Germany