1. Fundación IMDEA Nanociencia, Calle Faraday 9, Madrid 28049, Spain
2. Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Madrid 28223, Spain
3. Normandie University, UNICAEN, ENSICAEN, CNRS, GREYC, Caen 14000, France
4. Departamento Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid 28049, Spain
5. International School for Advanced Studies (SISSA/ISAS), Via Bonomea 265, Trieste 34136, Italy
6. mfd-Diagnostics GmbH, Mikroforum Ring 5, Wendelsheim 55234, Germany
7. Instituto de Ciencia de Materiales de Madrid (ICMM), CSIC, Calle Sor Juana Inés de la Cruz 3, Madrid 28049, Spain
8. Hospital Nacional de Parapléjicos, SESCAM, Finca La Peraleda s/n, Toledo 45071, Spain
9. Research Unit of “Design and Development of Biomaterials for Neural Regeneration”, Hospital Nacional de Parapléjicos, Joint Research Unit with CSIC, Toledo 45071, Spain
10. Dept. Física de Materiales, Universidad Complutense, Madrid 28040, Spain
11. Instituto “Nicolás Cabrera” and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid 28049, Spain