1. Department of Biomedical Engineering, Dongguk University, 3-26 Phill-Dong, Joong-Gu, Seoul, 100-715, Korea, Department of Measurement Science and Industrial Electrical Engineering, Divison of Nanobiotechnology, Lund University, Lund, Sweden, and Department of Chemistry, Sungkyunkwan University, 300 Cheoncheon-dong, Jangan-gu, Suwon, Gyeonggi-do 440-746, Korea