1. Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, United States
2. Center for Brain and Spinal Cord Repair, Department of Neuroscience, The Ohio State University, 460 West 12th Avenue, Columbus, Ohio 43210, United States
3. Materials Science and Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, United States