Electromagnetic fields (UHF) increase voltage sensitivity of membrane ion channels; possible indication of cell phone effect on living cells.
The effects of ultra high frequency (UHF) nonionizing electromagnetic fields (EMF) on the channel activities of nanopore forming protein, OmpF porin, were investigated. The voltage clamp technique was used to study the single channel activity of the pore in an artificial bilayer in the presence and absence of the electromagnetic fields at 910 to 990 MHz in real time. Channel activity patterns were used to address the effect of EMF on the dynamic, arrangement and dielectric properties of water molecules, as well as on the hydration state and arrangements of side chains lining the channel barrel. Based on the varied voltage sensitivity of the channel at different temperatures in the presence and absence of EMF, the amount of energy transferred to nano-environments of accessible groups was estimated to address the possible thermal effects of EMF. Our results show that the effects of EMF on channel activities are frequency dependent, with a maximum effect at 930 MHz. The frequency of channel gating and the voltage sensitivity is increased when the channel is exposed to EMF, while its conductance remains unchanged at all frequencies applied. We have not identified any changes in the capacitance and permeability of membrane in the presence of EMF. The effect of the EMF irradiated by cell phones is measured by Specific Absorption Rate (SAR) in artificial model of human head, Phantom. Thus, current approach applied to biological molecules and electrolytes might be considered as complement to evaluate safety of irradiating sources on biological matter at molecular level.
Laboratory of Membrane Biophysics and Macromolecules, Institute of Biochemistry and Biophysics, University of Tehran , Tehran , Iran .
N
N
Ketabi
H
H
Mobasheri
R
R
Faraji-Dana
D002462:Cell Membrane / Q000378:metabolism* / Q000528:radiation effects; D040421:Cell Phone; D002470:Cell Survival / Q000528:radiation effects; D025802:Electric Capacitance; D004560:Electricity; D004574:Electromagnetic Fields / Q000009:adverse effects*; D015640:Ion Channel Gating / Q000528:radiation effects*; D018272:Porins / Q000378:metabolism*; D013696:Temperature
C109237:OmpF protein; D018272:Porins
Biophysics; electromagnetic field; ion channel; voltage clamp