1. Research Center for Macromolecules and Biomaterials National Institute for Materials Science 1-2-1 Sengen Tsukuba Ibaraki 305-0047 Japan
2. PRESTO, JST 7 Gobancho, Chiyoda-ku Tokyo 102-0076 Japan
3. Research Center for Macromolecules and Biomaterials National Institute for Materials Science 1-1 Namiki Tsukuba Ibaraki 305-0044 Japan
4. Graduate School of Life Science Hokkaido University Kita 10, Nishi 8, Kita-ku Sapporo Hokkaido 060-0810 Japan