This work was financially supported by the Spanish Ministerio de Economía y Competitividad (Project No. CTQ2012-31157), the FP7 PEOPLE-2013-IRSES Marie Curie Actions programme (GMOsensor Project No. 612545) and co-financed by FEDER funds. CAPES/FAPEPI program for a predoctoral grant supported by the Ministry of Education of Brazil. R.M.-C. thanks Principado de Asturias government and FICYT for a Clarín postdoctoral contract.