Authors' Affiliations: Departments of 1Biomedical Engineering and 2Comparative Biomedical Sciences, 3Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York; 4Department of Veterinary Medicine, Colorado State University, Fort Collins, Colorado; and 5Laboratory for Translational Stem Cell Research, Weill Cornell Brain Tumor Center, Department of Neurological Surgery, Weill Cornell Medical College, New York (At 2013-12-01)