1. School of Materials Science and Engineering, and Center of Functional Biomaterials, Key Laboratory of Polymeric Composite Materials and Functional Materials of Ministry of EducationGD Research Center for Functional Biomaterials Engineering and TechnologySun Yat-sen University Guangzhou 510275 China
2. Department of Biomedical EngineeringColumbia University New York NY 10027 USA
3. Department of RadiologySun Yat-sen Memorial HospitalSun Yat-sen University Guangzhou 510080 China
4. Department of Materials Science and EngineeringJohns Hopkins University Baltimore MD 21205 USA