1. Institute of Micro and Nanomaterials, University of Ulm, 89081 Ulm, Germany
2. National Laser Centre, Peterfy Sandor Teaching Hospital, 1076 Budapest, Hungary
3. Department of Chemistry, Philipps University of Marburg, 35032 Marburg, Germany
4. Division of Prosthetic Dentistry, School of Dental Medicine, Philipps University, 35039 Marburg, Germany
5. Institute for Nanotechnology, Forschungszentrum Karlsruhe, 76021 Karlsruhe, Germany.