1. Department of Materials Science & Engineering, University of Washington, Seattle, Washington 98195, United States
2. Department of Neurosurgery, The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning 110032, China
3. Division of Oncology, University of Washington, Seattle, Washington 98195, United States
4. Department of Surgery, University of Washington, Seattle, Washington 98195, United States
5. Department of Neurological Surgery, University of Washington, Seattle, Washington 98195, United States