1. Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
2. Department of Biological Engineering, East China University of Science and Technology, Shanghai, China
3. Departments of Chemistry, Biochemistry, and Bioengineering, Institute for Genomic Biology, Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801