1. Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
2. National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
3. Los Alamos National Laboratory, Casa Grande Drive, Los Alamos, New Mexico 87544, United States
4. Department of Physiology, University of California, Los Angeles, California 90095, United States
5. California NanoSystems Institute, University of California, Los Angeles, California 90095, United States
6. Department of Physics, Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel