1. School of Mechanical Engineering Kookmin University Seoul 02707 Republic of Korea
2. Department of Biomedical Engineering Northwestern University Evanston IL 60208 USA
3. Querrey‐Simpson Institute for Bioelectronics Northwestern University Evanston IL 60208 USA
4. State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai 200240 China
5. Department of Civil and Environmental Engineering Mechanical Engineering and Materials Science and Engineering Northwestern University Evanston IL 60208 USA
6. Department of Materials Science and Engineering Northwestern University Evanston IL 60208 USA
7. Epicore Biosystems, Inc. Cambridge MA 02139 USA
8. Departments of Chemistry Biomedical Engineering and Electrical Engineering and Computer Science Northwestern University Evanston IL 60208 USA
9. Department of Neurological Surgery Northwestern University Evanston IL 60208 USA