Radio frequency magnetic field effects on molecular dynamics and iron uptake in cage proteins

Oscar Céspedes, Osamu Inomoto, Shoichi Kai, Yoshinori Nibu, Toshio Yamaguchi, Nobuyoshi Sakamoto, Tadahiro Akune, Masayoshi Inoue, Takanobu Kiss, Shoogo Ueno

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


The protein ferritin has a natural ferrihydrite nanoparticle that is superparamagnetic at room temperature. For native horse spleen ferritin, we measure the low field magnetic susceptibility of the nanoparticle as 2.2 x 10-6 m3 kg-1 and its Néel relaxation time at about 10-10 s. Superparamagnetic nanoparticles increase their internal energy when exposed to radio frequency magnetic fields due to the lag between magnetization and applied field. The energy is dissipated to the surrounding peptidic cage, altering the molecular dynamics and functioning of the protein. This leads to an increased population of low energy vibrational states under a magnetic field of 30 μT at 1 MHz, as measured via Raman spectroscopy. After 2h of exposure, the proteins have a reduced iron intake rate of about 20%. Our results open a new path for the study of non-thermal bioeffects of radio frequency magnetic fields at the molecular scale.

Original languageEnglish
Pages (from-to)311-317
Number of pages7
Issue number4
Publication statusPublished - May 2010

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Physiology
  • Radiology Nuclear Medicine and imaging


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