1. Research Center for Nanorobotics in Brain, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
2. School of Integrated Technology, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
3. School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
4. Korea Institute of Medical Microrobotics (KIMIRo), 43-26 Cheomdangwagi-ro, Buk-gu, Gwangju 61011, Republic of Korea