Konstantinos Ntokos, Maria-Thaleia Passia, Savvas Raptis, Aristotle University of Thessaloniki, Greece; Konstantina Tourlouki, Nanotypos, Greece; Nikolaos Kehagias, Institute of Nanoscience & Nanotechnology, NCSR, Demokritos, Greece; Emmanouil Kriezis, Traianos Yioultsis, Aristotle University of Thessaloniki, Greece