1. nanoBIC, Department of Inorganic and Organic Chemistry Inorganic Chemistry SectionUniversity of Barcelona Martí i Franquès 1–11 08028 Barcelona Spain
2. Instituto de Ciencia de Materiales de AragónCSIC and Universidad de Zaragoza Plaza San Francisco s/n 50009 Zaragoza Spain
3. Institut de Biotecnologia i de Biomedicina and Departament de Bioquímica i de Biologia MolecularUniversitat Autònoma de Barcelona, Bellaterra Barcelona Spain
4. Catalan Institution for Research and Advanced Studies (ICREA) Passeig Lluís Companys 23 08010 Barcelona Spain
5. Institute of Nanoscience and Nanotechnology (IN2UB) Universitat de Barcelona 08028 Barcelona Spain