1. Division of NanoMedicine, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095, United States
2. California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
3. Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, United States