1. Laboratory for Biomolecular Nanotechnology, MESA+ Institute, University of Twente, P.O. Box 207, 7500 AE Enschede, The Netherlands
2. Organic Chemistry Department, Universidad Autónoma de Madrid, 28049 Cantoblanco, Spain
3. Biomolecular Mass Spectrometry and Proteomics Group, Utrecht Institute of Pharmaceutical Science and Bijvoet Centre, Utrecht University and Netherlands Proteomics Centre, 3508 TC Utrecht, The Netherlands
4. IMDEA-Nanociencia, Facultad de Ciencias, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain