1. Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, School of Dentistry, University of California, Los Angeles, CA, USA
2. California NanoSystems Institute, University of California, Los Angeles, CA, USA
3. Department of Bioengineering, University of California, Los Angeles, CA, USA
4. Department of Chemistry, University of North Carolina, Chapel Hill, NC, USA