1. The Key Laboratory of Biomedical Information Engineering of Ministry of Education
2. School of Life Science and Technology
3. Xi'an Jiaotong University
4. Xi'an 710049
5. China
6. Centre for Nanotechnology and Regenerative Medicine
7. UCL Division of Surgery and Interventional Science
8. University College London
9. London WC1E 6AU
10. UK
11. Department of Biomedical Engineering
12. School of Engineering
13. Sun Yat-sen University
14. Guangzhou