1. Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois.
2. Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois.
3. Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois.
4. Beckman Institute for Advanced Science and Technology, Department of Electrical and Computer Engineering, and Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois.
5. Beckman Institute for Advanced Science and Technology, Department of Bioengineering, and Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois.
6. Beckman Institute for Advanced Science and Technology, Department of Electrical and Computer Engineering, Department of Bioengineering and College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois.