In vitro heat generation by ferrimagnetic maghemite microspheres for hyperthermic treatment of cancer under an alternating magnetic field

Masakazu Kawashita, Shinjiro Domi, Yasuhiro Saito, Masaaki Aoki, Yukihiro Ebisawa, Tadashi Kokubo, Takashi Saito, Mikio Takano, Norio Araki, Masahiro Hiraoka

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)

Abstract

Ferrimagnetic materials can be expected to be useful as thermo seeds for hyperthermic treatment of cancer, especially where the cancer is located in deep parts of body, as they can generate heat by magnetic hysteretic loss when they are placed in an alternating magnetic field. Recently, it was reported that ferrimagnetic maghemite (γ-Fe2O3) microspheres 20-30 μm in diameter prepared in aqueous solution can show excellent heat generating ability. However, these microspheres have many cracks on their surfaces. In this study, the preparation conditions for the microspheres was further optimized in order to obtain crack-free ferrimagnetic microspheres, and the in vitro heat generation of the obtained microspheres was measured in an agar phantom under an alternating magnetic field. Crack-free γ-Fe 2O3 microspheres 20-30 μm in diameter were obtained successfully. Their saturation magnetization and coercive force were 68 emu g-1 and 198 Oe, respectively. Their heat generation under an alternating magnetic field of 300 Oe at 100 kHz was estimated to be 42 W g -1. The microspheres showed in vitro heat generation when they were dispersed in an agar phantom and placed under an alternating magnetic field. It is believed that these microspheres may be useful for the in situ hyperthermic treatment of cancer.

Original languageEnglish
Pages (from-to)1897-1903
Number of pages7
JournalJournal of Materials Science: Materials in Medicine
Volume19
Issue number5
DOIs
Publication statusPublished - 2008 May 1

ASJC Scopus subject areas

  • Biophysics
  • Bioengineering
  • Biomaterials
  • Biomedical Engineering

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