1. Facultad de Química; Universidad Nacional Autónoma de México, Av. Insurgentes Sur 3000; Ciudad Universitaria, C.P. 10200 Mexico City Mexico
2. School of Chemistry; University of Glasgow; Glasgow G12 8QQ UK
3. NanoPETPharma GmbH, Luisencarrée; Robert-Koch-Platz 4 10115 Berlin Germany
4. Helmholtz-Zentrum Berlin für Materialien und Energie; 14109 Berlin Germany
5. Max Planck Institute of Colloids and Interfaces; Colloid Department; Am Mühlenberg 1 14476 Potsdam Germany
6. Current address: School of Biological and Chemical Sciences; Queen Mary University of London; Mile End Road London E1 4NS UK