1. Laboratory of General Biochemistry and Physical Pharmacy, Ghent Research Group on Nanomedicine, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, Ghent, Belgium
2. Physics of Fluids Group, MESA+ Institute for Nanotechnology and Technical Medical (TechMed) Center, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands