1. Small Biosystems Lab, Condensed Matter Physics Department, University of Barcelona, 08028 Barcelona, Spain
2. Physics and Astronomy Department, University of Padova, 35131 Padova, Italy
3. Laboratory of Nanoscale Biology, Institute of Bioengineering, School of Engineering, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne, Switzerland
4. SpliceBio, 08028 Barcelona, Spain