1. Instituto de Microelectrónica de Barcelona; IMB-CNM (CSIC); C/ del Til·lers. Campus Universitat Autònoma de Barcelona (UAB); 08193 Bellaterra Barcelona Spain
2. Department of Bioengineering; University of Washington; Seattle WA 98195 USA
3. Fuel Cell Research Lab (FCReL); School of Mechatronic Systems Engineering; Simon Fraser University; Surrey BC V3T 0A3 Canada
4. GIRO Joint Research Unit IRTA-UPC; Torre Marimon; 08140 Caldes de Montbui Barcelona Spain
5. Catalan Institution for Research and Advanced Studies (ICREA); Passeig Lluís Companys 23 08010 Barcelona Spain