1. Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221, USA
2. The Materials Science and Engineering Program, Department of Mechanical and Materials Engineering, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio 45221, USA
3. Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305-2115, USA
4. Med-X Institute, Shanghai Jiao Tong University, Shanghai 200030, People's Republic of China
5. James L. Winkle College of Pharmacy, University of Cincinnati, Cincinnati, Ohio 45267, USA
6. Shanghai East Hospital, The Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai 200120, People's Republic of China