Jae-Hyun Lee1, Jung-tak Jang1, Jin-sil Choi1, Seung Ho Moon1, Seung-hyun Noh1, Ji-wook Kim1, Jin-Gyu Kim2, Il-Sun Kim3, Kook In Park3 and Jinwoo Cheon1*
1Department of Chemistry, Yonsei University, Seoul, 120-749, Korea, 2Division of Electron Microscopic Research, Korea Basic Science Institute, Daejeon, 305-333, Korea, 3Department of Pediatrics and BK 21, Yonsei University College of Medicine, Seoul, 120-752, Korea.
Correspondence to: Jinwoo Cheon
The conversion of electromagnetic energy into heat by nanoparticles has the potential to be a powerful, non-invasive technique for biotechnology applications such as drug release1, 2, 3, disease treatment4, 5, 6 and remote control of single cell functions7, 8, 9, but poor conversion efficiencies have hindered practical applications so far10, 11. In this Letter, we demonstrate a significant increase in the efficiency of magnetic thermal induction by nanoparticles. We take advantage of the exchange coupling between a magnetically hard core and magnetically soft shell to tune the magnetic properties of the nanoparticle and maximize the specific loss power, which is a gauge of the conversion efficiency. The optimized core-shell magnetic nanoparticles have specific loss power values that are an order of magnitude larger than conventional iron-oxide nanoparticles. We also perform an antitumour study in mice, and find that the therapeutic efficacy of these nanoparticles is superior to that of a common anticancer drug.