1. Inorganic Chemistry Laboratory, Chemistry Department, National and Kapodistrian University of Athens, Panepistimiopolis, 157 71 Zografou, Greece
2. Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 153 41 Athens, Greece
3. Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, Viale G.B. Morgagni, 50, 50134 Florence, Italy