1. Dipartimento di Fisica, Università della Calabria, Rende, Italy
2. Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
3. Consiglio Nazionale delle Ricerche - Istituto di Nanotecnologia (CNR - Nanotec), c/o Università della Calabria, Ponte P. Bucci, 33/B, 87036 Rende (CS), Italy
4. Biological and Biomimetic Material Laboratory and Center for Biomimetic Sensor Science, School of Materials Science and Engineering, Nanyang Technological University (NTU), 50 Nanyang Avenue, Singapore 637553
5. School of Biological Sciences, Nanyang Technological University (NTU), 60 Nanyang Drive, Singapore 637551