1. Institute for Life and Medical Sciences, Kyoto University 1 Laboratory of Developmental Systems , , Kyoto 606-8507 , Japan
2. Graduate School of Engineering, Kyoto University 2 Department of Polymer Chemistry , , Kyoto 606-8507 , Japan
3. Institute for Life and Medical Sciences, Kyoto University 3 Laboratory of Biomechanics , , Kyoto 606-8507 , Japan
4. Institute for Advanced Study of Human Biology (WPI-ASHBi), Kyoto University, Yoshida-Konoe-Cho 4 , Sakyo-Ku, Kyoto 606-8501 , Japan