1. Field of Biophysics, Cornell University, Ithaca, New York 14853, United States
2. Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, United States
3. Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
4. Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, United States