This work was supported in part by the Plan Estatal de I+D+I 2013-2016 and the Instituto de Salud Carlos III (co-funding from FEDER, grant PI12/01861), FIS (PI12/00327), MINECO (BFU2010-17450), Marató de TV3 (416/C/2013-2030) and CIBER-BBN Nanomets Intramural Project, and used the CIBER-BBN Nanotoxicology Platform and the Protein Production Platform for its development. GOA and NBT groups are part of the Spanish NANBIOSIS Network for Nanomedicine. U.U. is supported by a Sara Borrell contract from ISCIII. P.A. is recipient of a Fellowship from the Josep Carreras Research Institute. A.V. received an ICREA ACADEMIA Award.