1. Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
2. Laboratory of Polymers and Biomaterials, Fondazione Istituto Italiano di Tecnologia, 16163 Genova, Italy
3. Electron Microscopy Facility, Fondazione Istituto Italiano di Tecnologia, 16163 Genova, Italy