Study type: Medical/biological study (experimental study)

Electromagnetic exposure of scaffold-free three-dimensional cell culture systems. med./bio.

Published in: Bioelectromagnetics 2011; 32 (5): 351-359

Aim of study (acc. to author)

To study the effects of electromagnetic field exposure on a scaffold-free (i.e. without synthetic polymers or biomaterials) three-dimensional (3D) cell culture system.

Background/further details

The study aimed to achieve an improved physiological relevance by a 3D in vitro model. Several studies have already revealed distinct differences between monolayer and 3D cell cultures in terms of cellular behavior. By using rotation-mediated scaffold-free spheroids histotypic self-organization is enabled.
In the first part of experiments, cardiac myocyte spheroids were exposed to pulsed electromagnetic fields (field 2). In a second part the pulse frequency of the electromagnetic field was adjusted to the beat rate of a single spheroid (field 3). By varying the pulse frequency in the range of 5-20%, possible direct interferences of electromagnetic field frequencies with the beat rate were explored. In positive controls the beat rate of spheroids was investigated as a function of temperature (field 1).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: CW
Exposure duration: continuous for 1 min
Exposure 2: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 1 min
Exposure 3: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 1 min

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 1 min
Additional info positive control
Modulation
Modulation type CW
Exposure setup
Exposure source
Setup TEM cell constructed as a 1000 mm long stripline consisting of a 1 mm tin-plated steel sheet and a septum at a distance of 50 mm; stripline equipped with a temperature controller; temperature controller switched off
Parameters
Measurand Value Type Method Mass Remarks
SAR 1 W/kg - calculated - within the spheroids

Exposure 2

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 1 min
Modulation
Modulation type pulsed
Duty cycle 50 %
Repetition frequency 8.3 Hz
Exposure setup
Exposure source
Setup temperature controller switched on
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 100 mW/kg - calculated - within the spheroids
SAR 250 mW/kg - calculated - within the spheroids

Exposure 3

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 1 min
Modulation
Modulation type pulsed
Repetition frequency 1 Hz
Additional info

pulse frequency adjusted to the beat rate

Exposure setup
Exposure source
Setup temperature controller switched on
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 100 mW/kg - calculated - within the spheroids

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • before exposure
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

None of the analyzed electrophysiological parameters were significantly changed under exposure. Thus, the data showed no influence of the electromagnetic field on cardiac contractions.
However, the data showed that spheroids under the present conditions are excellent candidates for electromagnetic field exposure experiments. Electromagnetic field disturbances due to the recording electrodes were only minor. Compared to monolayer cultures, spheroids are contractile for a longer period of time and thus are a promising cell culture system for long-term exposure studies.

Study character:

Study funded by

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