1. Department of Bioengineering School of Engineering University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
2. Department of Materials Engineering School of Engineering University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
3. Center for Disease Biology and Integrative Medicine Division of Clinical Biotechnology School of Medicine University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
4. Division of Tissue Engineering University of Tokyo Hospital 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
5. Precursory Research for Embryonic Science and Technology (Japan) Science and Technology Agency 4-1-8 Honcho, Kawaguchi-shi Saitama 332-0012 Japan