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.

By: Kowalczuk C, Yarwood G, Blackwell R, Priestner M, Sienkiewicz Z, Bouffler S, Ahmed I, Abd-Alhameed R, Excell P, Hodzic V, Davis C, Gammon R, Balzano Q

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

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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

demodulation ability of living cells and tissues (second harmonic generation)

Exposure

- RF field
- CW continuous wave
- mobile communications
- mobile phone

Exposure	Parameters
Exposure 1: 880–890 MHz Modulation type: CW Exposure duration: < 10 minutes (typically, a second harmonic test took around 2-3 min.)	power: 0.1 mW power: 1 mW SAR: 10.6 mW/g (+/- 0.4 mW/g for cells at 1 mW) SAR: 2.5 mW/g (+/- 0.2 mW/g for tissue slices at 1 mW)

Exposure 1

Main characteristics

Frequency	880–890 MHz
Type	electromagnetic field
Exposure duration	< 10 minutes (typically, a second harmonic test took around 2-3 min.)

Modulation

Modulation type	CW

Exposure setup

Exposure source	vector network analyzer
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

Balzano Q et al. (2008): A doubly resonant cavity for detection of RF demodulation by living cells
Balzano Q (2002): Proposed test for detection of nonlinear responses in biological preparations exposed to RF energy

Exposed system:

intact cell/cell culture
tissue slices
cell suspensions
IMR 32 (human neuroblastoma cells), G361 (human melanoma cells), HF-19 (human fibroblasts), N2a (murine neuroblastoma cells; differentiated and non-differentiated); CHO (Chinese hamster ovary) cells

Methods Endpoint/measurement parameters/methodology

cell viability/cell division/proliferation: cell viability (trypan blue exclusion assay; resazurin reduction assay; oxygen consumption)
demodulation ability of living cells and tissues (second harmonic generation; spectrum analyzer)

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:

medical/biological study
experimental study
full/main study
blind study

Study funded by

Mobile Telecommunications and Health Research (MTHR), UK

Schmid MR et al. (2012): Sleep EEG alterations: effects of pulsed magnetic fields versus pulse-modulated radio frequency electromagnetic fields
Balzano Q et al. (2008): A doubly resonant cavity for detection of RF demodulation by living cells
Balzano Q et al. (2003): RF nonlinear interactions in living cells-I: nonequilibrium thermodynamic theory
Balzano Q (2002): Proposed test for detection of nonlinear responses in biological preparations exposed to RF energy