1. Nanobioelectronics & Biosensors Group, Catalan Institute of Nanotechnology, 08193, Bellaterra, Barcelona, Spain
2. Polytechnic University of Catalonia, ESAII department, 08028, Barcelona, Spain
3. Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain
4. Catalan Institution for Research and Advanced Studies (ICREA), 08010, Barcelona, Spain