1. Department of Physics, University of Illinois, Urbana-Champaign, Urbana, United States
2. Center for Biophysics and Quantitative Biology, University of Illinois, Urbana-Champaign, Urbana, United States
3. Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, United States
4. Center for the Physics of Living Cells, University of Illinois, Urbana-Champaign, Urbana, United States