1. Department of Biotechnology; Yonsei University; 50 Yonsei-ro Seodaemun-gu Seoul 120-749 Republic of Korea
2. Center for Biomaterials; Korea Institute of Science and Technology; Seoul 136-650 Republic of Korea
3. Nuffield Department of Orthopaedics; Rheumatology and Musculoskeletal Sciences; University of Oxford; Oxford OX3 7LD U.K.
4. Department of Bioengineering; Hanyang University; Seoul 133-791 Republic of Korea