1 Unit of Biophysics and Bioengineering, School of Medicine and Health Sciences, Universitat de Barcelona, Barcelona, Spain.
2 Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Barcelona, Spain.
3 Department of Electronics and Biomedical Engineering, Universitat de Barcelona, Barcelona, Spain.
4 Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Barcelona, Spain; Department of Electronics and Biomedical Engineering, Universitat de Barcelona, Barcelona, Spain.
5 Unit of Biophysics and Bioengineering, School of Medicine and Health Sciences, Universitat de Barcelona, Barcelona, Spain; Institut Investigacions Biomediques August Pi Sunyer, Barcelona, Spain; CIBER de Enfermedades Respiratorias, Madrid, Spain. Electronic address: rfarre@ub.edu.