title: Radio frequency magnetic field effects on molecular dynamics and iron uptake in cage proteins.
abstract: 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.
authors.affiliation: Department of Applied Quantum Physics, Graduate School of Engineering, Kyushu University, Fukuoka, Japan. o.cespedes@leeds.ac.uk
authors.forename: Oscar
authors.initials: O
authors.lastname: Céspedes
authors.forename: Osamu
authors.initials: O
authors.lastname: Inomoto
authors.forename: Shoichi
authors.initials: S
authors.lastname: Kai
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Nibu
authors.forename: Toshio
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Sakamoto
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Akune
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Inoue
authors.forename: Takanobu
authors.initials: T
authors.lastname: Kiss
authors.forename: Shoogo
authors.initials: S
authors.lastname: Ueno
mesh_terms: D000818:Animals; D005293:Ferritins / Q000737:chemistry / Q000378:metabolism*; D006736:Horses; D007501:Iron / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000737:chemistry; D008280:Magnetics; D056004:Molecular Dynamics Simulation; D053758:Nanoparticles / Q000737:chemistry; D011846:Radio Waves; D013059:Spectrum Analysis, Raman
chemical_list: D007502:Iron Chelating Agents; D005293:Ferritins; D007501:Iron