1. Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea.
2. School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 151-742, Republic of Korea.
3. Interdisciplinary Program for Bioengineering, Seoul National University, Seoul 151-742, Republic of Korea.
4. School of Mechanical Engineering, Pusan National University, Busan 609-735, Republic of Korea.
5. Department of Physics, Inha University, Incheon 402-751, Republic of Korea.