1. Department of Biomedical Engineering Tufts University Medford MA 02155 USA
2. Department of Biochemistry Institute for Protein Design University of Washington Seattle WA 98195 USA
3. Department of Bioengineering University of Washington Seattle WA 98195 USA
4. Howard Hughes Medical Institute University of Washington Seattle WA 98195 USA
5. Department of Physics Tufts University Medford MA 02155 USA
6. Laboratory for Living Devices Tufts University Medford MA 02155 USA
7. Department of Electrical and Computer Engineering Tufts University Medford MA 02155 USA