Medical/biological study (experimental study)

Exposure of magnetic bacteria to simulated mobile phone-type RF radiation has no impact on mortality med./bio.

By: Cranfield CG, Wieser HG, Dobson J

Published in: IEEE Trans Nanobioscience 2003; 2 (3): 146-149

Aim of study (acc. to author)

To examine the effect of mobile phone radio frequency emissions on magnetite-containing (magnetic) bacteria.

Background/further details

Magnetic and electron microscopic analyses of human brain tissue have revealed that biogenic magnetite in human brain tissue is similar to that of magnetite-containing bacteria. Magnetite-containing bacteria cells and closely related nonmagnetic bacteria cells (control group) were exposed and sham-exposed for 30 min.

Endpoint

cell viability/cell division/proliferation: cell mortality

Exposure

- mobile communications
- digital mobile phone
- GSM

Exposure	Parameters
Exposure 1: 1.8 GHz Modulation type: pulsed Exposure duration: continuous for 30 min	SAR: 2 W/kg maximum

Exposure 1

Main characteristics

Frequency	1.8 GHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 30 min

Modulation

Modulation type	pulsed
Repetition frequency	217 Hz
Additional info	The GSM signal included an 8-Hz component (every 26th pulse was blanked) and a 2-Hz DTX component for 34% of the time.

Exposure setup

Exposure source	waveguide REFLEX exposure system
Chamber	Two waveguides housed in a temperature-controlled CO₂ incubator set at 30 °C were selected at random and blinded by a computer for RF or sham exposure.
Setup	Six tissue culture Petri dishes (40 mm x 12 mm) containing 3 ml of equally concentrated magnetotactic bacterial cells or CC-26 cells and sealed with laboratory film to make them airtight were placed in each waveguide.
Sham exposure	A sham exposure was conducted.
Additional info	The exposure system provided very well controlled dosimetry and continuous monitoring of temperature conditions.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	2 W/kg	maximum	-	-	-

Exposed system:

bacterium
magnetite-containing bacteria (Magnetospirillum magnetotacticum), nonmagnetic bacteria (CC-26 strain of Proteobacteria)

Methods Endpoint/measurement parameters/methodology

cell viability/cell division/proliferation: cell mortality (fluorescence-spectrophotometry)

Investigated system:

bacterium

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Both the magnetite-containing bacteria and the nonmagnetite bacterial strain did not show any consistent bioeffects due to radio frequency exposure. Group comparisons did not reveal significant differences in cell mortality.
In the present study previous findings (see publication 11548) could not be replicated.

Study character:

Study funded by

Forschungsstiftung Mobilkommunikation (FSM; Research Foundation on Mobile Communication; at the Swiss Federal Institute of Technology Zurich (ETH)), Switzerland

Replicated studies

Cranfield C et al. (2003): Preliminary evaluation of nanoscale biogenic magnetite-based ferromagnetic transduction mechanisms for mobile phone bioeffects

Pan W et al. (2010): Effects of pulsed magnetic field on the formation of magnetosomes in the Magnetospirillum sp. strain AMB-1
Wang X et al. (2008): Sinusoidal magnetic field stimulates magnetosome formation and affects mamA, mms13, mms6, and magA expression in Magnetospirillum magneticum AMB-1
Kirschvink JL et al. (2001): Magnetite-based magnetoreception
Stewart Z et al. (2000): Evidence for mechanosensitive trans-membrane ion channels of small conductance in magnetotactic bacteria
Kirschvink JL et al. (1992): Magnetite in human tissues: a mechanism for the biological effects of weak ELF magnetic fields