1. Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
2. Department of Mechanical Engineering, University of California, Berkeley, 6141 Etcheverry Hall, Berkeley, CA 94720, USA.
3. Marine Biology Research Division, Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093, USA.
4. Department of Mechanical and Aerospace Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
5. Materials Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.