1. Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California, USA
2. Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, USA
3. Department of Chemistry, Stanford University, Stanford, California, USA
4. Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
5. California Nano Systems Institute, University of California, Los Angeles, Los Angeles, California, USA