1. Institute of Tissue
Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714, South Korea
2. Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 330-714, South Korea
3. Department of Biomedical Engineering, Columbia University, New York, New York 10027, United States
4. Department
of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714, South Korea