As the applications and commercial uses of millimeter- and submillimeter-waves grow, we should take a more detailed look at the impact this frequency range has on biological systems. This paper examines one specific effect of low-level (10-50 times the MPE - maximum permissible

exposure) 60 GHz CW RF power on cells – the opening of voltage sensitive cation channels

Pikov, Victor

Siegel, Peter H.

English

Caltech Authors - Main

Abstract— As the applications and commercial uses of 
millimeter- and submillimeter-waves grow, we should take a 
more detailed look at the impact this frequency range has on 
biological systems. This paper examines one specific effect of 
low-level (10-50 times the MPE - maximum permissible 
exposure) 60 GHz CW RF power on cells – the opening of voltage 
sensitive cation channels. 
I. INTRODUCTION AND BACKGROUND
HE proposed widespread use of millimeter wave 
generators for wireless telecommunications [1] should 
have prompted renewed scientific interest in the effects of this 
wavelength range on biologic materials and organisms. Yet 
there is little or no funding from US Federal Agencies, and by 
extension, very few research groups working in this area. 
Several recent investigations outside the US [e.g. 2-3] have 
noted significant impact from millimeter wave exposures that 
are not that much higher than the current MPE limits of 
1mW/cm2. In at least one set of experiments [4] millimeter 
wave heating of skate skin had the opposite effect on nerve
activity as general radiant heating, causing a suppression of 
neuronal firing rather than an enhancement. Higher levels of 
power (61 GHz, 190mW/cm2) have resulted in the appearance 
of cation channels in snail neuron membranes [5].
II. EXPERIMENTS
In our experiments we have begun to examine the impact of 
modest levels of RF power (10-100 mW/cm2) on specific cell 
processes, with the hope that at least some of these processes 
can be controlled with the application of millimeter waves.  As 
a first step to understanding where the RF energy distributes in 
a microscopic region in and around cells, we developed a 
non-contact method of monitoring the temperature of 
individual live cells in media. The technique uses microscopic 
Raman spectroscopy to monitor temperature dependent 
changes in the O-H vibrational modes of water at optical 
wavelengths, where penetration and scattering is not a serious 
issue as it is in IR spectroscopy. We were able to correlate and 
record changes in the measured spectra of DI water, cells in 
RPMI (Roswell Park Memorial Institute) media and cells in 
PBS (phosphate buffered saline) as the temperature was 
changed from 25-40C.  We were also able to record the 
temperature rise of cells in RPMI when exposed to modest 
levels (up to 100 mW/cm2) of millimeter wave power for 2 
minutes, and showed that these temperatures were higher than 
those that would be recorded by a commercial IR camera 
focused on the cells plus the surrounding media. 
In a more recent experiment, still preliminary at this 
juncture, we transfected the peGFP-F vector into an 
immortalized line of human derived lung cells (designation 
H1299). The resultant fGFP (farnesylated Green Fluorescent 
Protein) locates on the inner cell membrane where it fluoresces 
green (520nm) upon exposure to UV (490nm). Using oxonol as 
a quenching agent in the surrounding media we performed a 
single FRET (Förster resonance energy transfer) experiment to
look for the appearance of nanoporation or cation channels in 
the cell membrane upon exposure to millimeter waves. If the 
oxonol traverses the membrane the resulting fluorescent 
signature shifts from green to red according to the FRET 
process. The figure below shows the results of the experiment,
where not only did the millimeter-waves (50 GHz at 
approximately 15mW/cm2 for 2 minutes) induce ion channels 
to open up, but they allowed the channels to reseal upon 
cessation of the RF exposure after 3 minutes.
Although only a single experiment has been performed to 
date the data is intriguing enough to lead us to conclude that 
millimeter waves may indeed have more subtle effects upon 
biological systems than may have previously been thought. 
Many more experiments (and proposals) are planned.
REFERENCES
[1]. FCC (2008) Millimeter Wave 70-80-90 GHz Service. 
In: http://wirelessfccgov/services/indexhtm?job=service_home&id=millimeter_w
ave [2]. S.M. Minasyan, G.Y. Grigoryan, S.G. Saakyan, A.A. Akhumyan, V.P. 
Kalantaryan, “Effects of the action of microwave-frequency electromagnetic 
radiation on the spike activity of neurons in the supraoptic nucleus of the 
hypothalamus in rats,” Neurosci Behav Physiol 37:175-180, 2007.
[3]. A.G. Pakhomov, H.K. Prol, S.P. Mathur, Y. Akyel, C.B. Campbell,”Search 
for frequency-specific effects of millimeter-wave radiation on isolated nerve 
function,” Bioelectromagnetics 18:324-334, 1997.
[4]. A.Y. Sazonov, V.D. Avelev, “Research of biophysical mechanisms of 
mm-wave effects with use of the bio-technical complex on the basis of skate 
electroreceptors,” Millimeter Waves Med Biol 28:110-115, 2000.
[5]. S.I. Alekseev and M.C. Ziskin, “Effects of millimeter waves on ionic currents 
of Lymnaea neurons,” Bioelectromagnetics 20:24-33, 1999.
Peter H. Siegela and Victor Pikovb
a California Institute of Technology, Pasadena, CA 91125 USA
b Huntington Medical Research Institute, Pasadena, CA 91105 USA
Impact of Low Intensity Millimeter-Waves on Cell Membrane 
Permeability
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Impact of Low Intensity Millimeter-Waves on Cell Membrane

Permeability

Campbell,”Search for frequency-specific effects of millimeter-wave radiation on isolated nerve function,” Bioelectromagnetics 18:324-334,

Effects of millimeter waves on ionic currents of Lymnaea neurons,” Bioelectromagnetics 20:24-33, 1999. Peter H. Siegel aand Victor Pikov b a California Institute of Technology,

Effects of millimeter waves on ionic currents of Lymnaea neurons,” Bioelectromagnetics 20:24-33, 1999. Peter H. Siegela and Victor Pikovb a California Institute of Technology,

Millimeter Wave 70-80-90 GHz Service. In: http://wirelessfccgov/services/indexhtm?job=service_home&id=millimeter_w ave [2].

Research of biophysical mechanisms of mm-wave effects with use of the bio-technical complex on the basis of skate electroreceptors,”

http://authors.library.caltech.edu/20712/1/Siegel2009p118112009_34Th_International_Conference_On_Infrared_Millimeter_And_Terahertz_Waves_Vols_1_And_2.pdf

Impact of Low Intensity Millimeter-Waves on Cell Membrane Permeability

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