[1] Chinese Acad Med Sci & Peking Union Med Coll, Peking Union Med Coll Hosp, Dept Orthopaed, Beijing 100730, Peoples R China
[2] CNR, Nanosci Inst, Natl Enterprise Nanosci & Nanotechnol, I-56127 Pisa, Italy
[3] Univ Pisa, Dept Phys, I-56127 Pisa, Italy
[4] Beijing Univ Chem Technol, Beijing Lab Biomed Mat, Beijing 100029, Peoples R China