Study type: Medical/biological study (experimental study)

Absence of nonlinear responses in cells and tissues exposed to RF energy at mobile phone frequencies using a doubly resonant cavity. med./bio.

Published in: Bioelectromagnetics 2010; 31 (7): 556-565

Aim of study (acc. to editor)

The authors tested the hypothesis whether the electric and magnetic structures of cells exhibit the ability to demodulate radiofrequency carrier signals (i.e. to extract the low frequency component from the radiofrequency signal). The study was performed to investigate the possibility of the existence of a non-thermal interaction mechanism of radiofrequency electromagnetic fields.

Background/further details

If this mechanism would exist and biological cells and tissues could demodulate a radiofrequency signal, then they would be exposed to low frequency fields similar to those of biological processes and, therefore, with the potential for biological activity.
If the mechansim would exist it could be detected by the generation of a second harmonic signal upon exposure of the sample (i.e. by generation of double exposure frequency mediated by the sample). A doubly resonant cavity was used approaching the ultimate limits of physical sensitivity.
17 different cell suspensions (human lymphocytes and mouse bone marrow cells), adherent cells (different cell lines), Chinese hamster ovary cells and thin sections or slices of mouse tissues (brain, kidney, muscle, liver, spleen, testis, heart and diaphragm) were used. Aditionally, viable and non-viable samples were tested. Over 500 cell and tissue samples were exposed. The biological samples were selected to encompass varying degrees of electrical excitability.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 880–890 MHz
Modulation type: CW
Exposure duration: < 10 minutes (typically, a second harmonic test took around 2-3 min.)

Exposure 1

Main characteristics
Frequency 880–890 MHz
Type
Exposure duration < 10 minutes (typically, a second harmonic test took around 2-3 min.)
Modulation
Modulation type CW
Exposure setup
Exposure source
Setup cylindrical, gold-plated 27.54 cm long aluminum cavity with an inner diamter of 25 cm and two antennas; polycarbonate shelf placed in the center (position of E-field maximum) to support the Petri dishes; cavity placed inside an incubator; TE113 mode of the cavity tuned to coincide with twice the resonant frequency of the TE111 mode
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 0.1 mW - - - -
power 1 mW - - - -
SAR 10.6 mW/g - calculated - +/- 0.4 mW/g for cells at 1 mW
SAR 2.5 mW/g - calculated - +/- 0.2 mW/g for tissue slices at 1 mW

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

No consistent second harmonic of the incident continuous wave signals was detected. Therefore, these data do not support the hypothesis that living cells can demodulate radiofrequency energy, since second harmonic generation is the necessary and sufficient condition for demodulation.

Study character:

Study funded by

Related articles