1. Department of Materials, Department of Physics, and Department of Molecular, Cellular, & Developmental Biology, University of California, Santa Barbara, California 93106;,
2. Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106
3. Current address: Lehrstuhl für Zellbiophysik E27, Technische Universität München, 85748 Garching, Germany;
4. Current address: Department of Condensed Matter Physics, School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv, Israel;
5. Materials Research Laboratory, University of California, Santa Barbara, California 93106;