ID Number		1931
Study Type		In Vitro
Model		0.25-2 MHz exposure to purified ferritin protein and analysis of binding affinity to Fe++
Details		Purified apoferritin and ferritin protein from horse spleen was exposed to frequencies ranging from 0.25 (at 120 mictoT), 1 MHz (30 mictoT), to 2 MHz (at 15 microT) using Helmholtz coils. The authors report a change in the vibrational energy of the ferritin protein in the presence of the field causing a decrease in the affinity for Fe++. The authors propose a mechanism of alterning the 3D structure of the protein iron cage complex. The effects were not interpreted to be a result of any temperature increase. AUTHORS' ABSTRACT: Cespedes, Ueno et al. 2010 (IEEE #6290): 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) m(3) 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 microT at 1 MHz, as measured via Raman spectroscopy. After 2 h 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.
Findings		Effects
Status		Completed With Publication
Principal Investigator		Engineering Kyushu University, Japan - ueno@athena.ap.kyushu-u.ac.jp
Funding Agency		Ministry Ed, Sci, Japan
Country		JAPAN
References		Cespedes, O et al. Bioelectromagnetics, (2009) 30:336-342 Cespedes, O et al. Bioelectromagnetics., (2010) 31:311-317
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