1. Chemistry Department, Federal University of São Carlos (UFSCar), P.O. Box 676, CEP 13565-905 São Carlos, São Paulo, Brazil
2. National Laboratory for Nanotechnology in Agribusiness (LNNA), Embrapa Instrumentação, 13560-970 São Carlos, São Paulo, Brazil
3. Institute of Bioelectronics (PGI-8/ICS-8), Forschungszentrum Jülich, 52425 Jülich, Germany
4. Neuroelectronics, IMETUM, Department of Electrical and Computer Engineering, Technical University of Munich (TUM), Germany and Bernstein Center for Computational Neuroscience Munich, Boltzmannstr. 11, 85748 Garching, Germany