1. George W. Woodruff School of Mechanical EngineeringInstitute for Electronics and NanotechnologyGeorgia Institute of Technology Atlanta GA 30332 USA
2. School of Intelligent Mechatronics EngineeringSejong University Seoul 05006 Republic of Korea
3. Department of Mechanical EngineeringUniversity of South Alabama Mobile AL 36608 USA
4. Nell Hodgson Woodruff School of NursingEmory University Atlanta GA 30322 USA
5. Wallace H. Coulter Department of Biomedical EngineeringParker H. Petit Institute for Bioengineering and BiosciencesInstitute for MaterialsNeural Engineering CenterInstitute for Robotics and Intelligent MachinesGeorgia Institute of Technology and Emory University Atlanta GA 30332 USA