1. Materials Science and Engineering Program University of California, San Diego La Jolla CA 92093 USA
2. Department of Bioengineering University of California, San Diego La Jolla CA 92093 USA
3. Department of Nanoengineering University of California, San Diego La Jolla CA 92093 USA
4. Department of Electrical and Computer Engineering University of California, San Diego La Jolla CA 92093 USA
5. Department of Physics University of California, San Diego La Jolla CA 92093 USA
6. Department of Anesthesiology University of California, San Diego La Jolla CA 92093 USA
7. GI Motility and Physiology Program University of California, San Diego La Jolla CA 92093 USA