1. Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, U.S.A
2. Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, U.S.A
3. Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, U.S.A
4. Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, U.S.A