1. Division of Biology & Bioengineering, California Institute of Technology, Pasadena, CA, U.S.A.
2. Division of Chemistry & Chemical Engineering, California Institute of Technology
3. Department of Bioengineering, Department of Chemistry and Biochemistry, and California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, U.S.A.
4. Division of Geological & Planetary Sciences, California Institute of Technology