The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation

Williams, Catrin F. ORCID: https://orcid.org/0000-0001-8619-2581, Geroni, Gilles M., Pirog, Antoine, Lloyd, David ORCID: https://orcid.org/0000-0002-5656-0571, Lees, Jonathan ORCID: https://orcid.org/0000-0002-6217-7552 and Porch, Adrian ORCID: https://orcid.org/0000-0001-5293-8883 2016. The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation. Applied Physics Letters 109 (9) , 093701. 10.1063/1.4961970

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Abstract

Electromagnetic fields (EMFs) are ubiquitous in the digital world we inhabit, with microwave and millimetre wave sources of non-ionizing radiation employed extensively in electronics and communications, e.g., in mobile phones and Wi-Fi. Indeed, the advent of 5G systems and the “internet of things” is likely to lead to massive densification of wireless networks. Whilst the thermal effects of EMFs on biological systems are well characterised, their putative non-thermal effects remain a controversial subject. Here, we use the bioluminescent marine bacterium, Vibrio fischeri, to monitor the effects of pulsed microwave electromagnetic fields, of nominal frequency 2.5 GHz, on light emission. Separated electric and magnetic field effects were investigated using a resonant microwave cavity, within which the maxima of each field are separated. For pulsed electric field exposure, the bacteria gave reproducible responses and recovery in light emission. At the lowest pulsed duty cycle (1.25%) and after short durations (100 ms) of exposure to the electric field at power levels of 4.5 W rms, we observed an initial stimulation of bioluminescence, whereas successive microwave pulses became inhibitory. Much of this behaviour is due to thermal effects, as the bacterial light output is very sensitive to the local temperature. Conversely, magnetic field exposure gave no measurable short-term responses even at the highest power levels of 32 W rms. Thus, we were able to detect, de-convolute, and evaluate independently the effects of separated electric and magnetic fields on exposure of a luminescent biological system to microwave irradiation.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Biosciences Engineering
Additional Information:	PDF uploaded in accordance with publisher's polices at http://www.sherpa.ac.uk/romeo/issn/0003-6951/ (accessed 9.9.16).
Publisher:	AIP Publishing
ISSN:	0003-6951
Funders:	Sêr Cymru National Research Network in Advanced Engineering and Materials
Date of First Compliant Deposit:	6 September 2016
Date of Acceptance:	18 August 2016
Last Modified:	10 Nov 2023 18:18
URI:	https://orca.cardiff.ac.uk/id/eprint/94287

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