1. Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, P. R. China
2. Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, and Innovative Orthopaedic Biomaterial and Drug Translational Research Laboratory of Li Ka Shing Institute of Health, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, P. R. China
3. Department of Physics, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, P. R. China