1. Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, USA
2. UCLA-DOE Institute for Genomics and Proteomics, University of California Los Angeles, Los Angeles, California 90095, USA
3. Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel
4. Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
5. California NanoSystems Institute, University of California Los Angeles, Los Angeles, California 90095, USA