Electromagnetic radiation interacts with living matter through many frequency dependent mechanisms, causing effects including DNA damage and mutation. The effects of millimetre waves (MMWs), with wavelengths 1 – 10 mm and frequencies 30 – 300 GHz, on biological processes are less understood than other frequencies as strong attenuation by atmospheric oxygen results in low natural exposures.
However, while non-ionising, MMWs have non-trivial effects on humans, with therapeutic applications utilising MMWs to treat a range of ailments emerging in several Eastern European nations. Additionally, multiple frequency bands within this range are being adopted in 5G mobile networking technologies, establishing the importance of investigating the biological effects from the context of both increased natural exposure and potential medical applications.
Studies show that exposure to MMWs induces numerous biological responses, including changes to the properties of biological membranes[1], altered neuronal action potentials[2] and modified gene expression in cells[3]. However, the mechanisms describing these effects remain unknown. Initially attributed to the thermal effects of absorption, it has been shown that the changes in gene expression are distinct from heat shock responses and are now thought to arise from interactions with the genome[4].
G-quadruplexes and i-motifs are sequence specific DNA secondary structures occurring within G- and C-rich regions, respectively, that contribute to transcriptional regulation[5]. Many proposed models for MMW interactions with the genome describe conditions that may alter formation of these structures, including the induction of resonances causing transient single strandedness.
I will demonstrate the effect of MMWs on biological processes in human fibroblasts, describing cellular activation and modification of DNA secondary structure formation. We observe MMWs induce a fibrotic response, increasing the production and deposition of structured collagen. During this process G-quadruplex and i-motif populations are simultaneously altered. This work is the first to describe the direct effects of MMW exposure on the genome.