1. Key Laboratory of Oral Medicine, Guangzhou Institute of Oral DiseaseStomatology HospitalDepartment of Biomedical EngineeringSchool of Basic Medical SciencesGuangzhou Medical University Guangzhou 511436 P. R. China
2. Nanobiomedical CenterSchool of Life ScienceInner Mongolia Agricultural University 306 Zhaowuda Road Hohhot 010018 P. R. China
3. Department of BioengineeringUniversity of California San Diego 9500 Gilman Drive La Jolla CA 92093 USA
4. Materials Science and Engineering Program andDepartment of Mechanical and Aerospace EngineeringUniversity of California San Diego 9500 Gilman Drive La Jolla CA 92093 USA
5. State Key Laboratory of Respiratory DiseaseThe Sixth Affiliated HospitalDepartment of Biomedical EngineeringSchool of Basic Medical SciencesGuangzhou Medical University Guangzhou 511436 P. R. China