1. Jiangsu Provincial Key Laboratory of Advanced Robotics, School of Mechanical and Electric Engineering, Soochow University, Suzhou 215123, China
2. Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576
3. Department of Mechanical Engineering & Berkeley Sensor and Actuator Center, University of California at Berkeley, Berkeley, California 94720-1740, USA
4. Hybrid-Integrated Flexible (Stretchable) Electronic Systems Program, National University of Singapore, E6 #05-4, 5 Engineering Drive 1, Singapore 117608
5. NUS Suzhou Research Institute (NUSRI), Suzhou Industrial Park, Suzhou 215123, People's Republic of China
6. NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore 117456
7. Center for Intelligent Sensors and MEMS, National University of Singapore, E6 #05-11F, 5 Engineering Drive 1, Singapore 117608
8. Department of Bioengineering, University of California at Berkeley, Berkeley, California 94720-1740, USA