1. Materials Science Division, Lawrence Berkeley National Laboratory and Department of Chemistry, University of California, Berkeley, CA 94720, USA.
2. The Kavli Foundation, Oxnard, CA 93030, USA.
3. Department of Genetics, Harvard Medical School and Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA.
4. Howard Hughes Medical Institute (HHMI) and Departments of Bioengineering and Psychiatry, Stanford University, Stanford, CA 94305, USA.
5. Rehabilitation Research and Development Service, Veteran Affairs Medical Center, Providence, RI 02908, USA and Brown Institute of Brain Science, Department of Neuroscience and School of Engineering, Brown University, Providence, RI 02912, USA.
6. Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA 92093, USA.
7. Kavli Institute at Cornell for Nanoscale Science, Department of Physics, Cornell University, Ithaca, NY 14850, USA.
8. Kavli Nanoscience Institute and Departments of Physics, Applied Physics, and Bioengineering, California Institute of Technology, Pasadena, CA 91125, USA.
9. HHMI, Computational Neurobiology Laboratory, Salk Institute, La Jolla, CA 92037, USA and Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
10. California NanoSystems Institute, Department of Chemistry and Biochemistry, and Department of Materials Science and Engineering, University of California at Los Angeles, Los Angeles, CA 90095, USA.
11. HHMI, Departments of Biological Sciences and Neuroscience, Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA.