1. Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, School of Dentistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
2. California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
3. Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA.
4. Division of Diagnostic and Surgical Sciences, School of Dentistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.