1. Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Korea.
2. Interdisciplinary Program in Stem Cell Biology, College of Medicine, Seoul National University, Seoul 03080, Korea.
3. Department of Plastic and Reconstructive Surgery, Institute of Human-Environment Interface Biology, College of Medicine, Seoul National University, Seoul 03080, Korea.
4. Institute of Advanced Machines and Design, Seoul National University, Seoul 08826, Korea.