Authors: M. Djuari, M. Engelke, J. Höfert, C. Ziemann, A. Bitsch
10th German Pharm-Tox Summit 2025. Naunyn-Schmiedeberg’s Arch Pharmacol (2025), doi: 10.1007/s00210-025-03881-x.
Abstract
Smartphones are nowadays an indispensable part of everyday life, which leads to an increasing need for faster, more accessible, and more stable mobile phone system. The latest publicly released innovation in mobile phone technology is the so-called ffth generation (5G New Radio). This technology not only uses frequencies of the previous generations (<6 GHz), known as frequency range 1 (FR1), but also higher frequencies in the millimeter wave range (24.25 – 52.6 GHz; mmWave), also known as frequency range 2 (FR2). While FR1 has intensively been investigated over the last 30 years, there are only a few studies on FR2 to date. Therefore, the SEAWave project, funded by the European Union Horizon program with grant number HORIZONHLTH-2021- ENVHLTH-02-01, aims to investigate amongst others biological efects of FR2 in vitro in primary human skin cells. The skin represents the most important organ for adverse efects of 5G, due to very low penetration depth of mmWaves. Cell models for (geno) toxicity testing including oxidative DNA damage (hOGG1-modifed alkaline comet assay) comprised low-pigmented adult and juvenile epidermal keratinocytes (NHEK) and low-pigmented adult epidermal melanocytes (NHEM). After cell characterization regarding growth behavior, cells were exposed blinded to FR2 at three power densities, i.e., sham, 3.33 W/m2, and 10 W/m2 for 4 or 24 h, before subjected to the hOGG1-modifed comet assay. Cytotoxicity was determined in parallel by automatic cell counting. After 4 h of exposure, no cytotoxicity was detected in all tested skin cell models, and FR2 didn”t mediate any signifcant increase in median- based mean tail intensity without hOGG1 treatment. Maximum fold change (mfc) amounted to 0.91 and 1.09 in adult and juvenile NHEK, and 1.2 in NHEM. Furthermore, no oxidative DNA damage was detected in all exposed skin models, when comparing slides without and with hOGG1 treatment. After 24 h of FR2 exposure again no cytotoxic and genotoxic efects were detected, with mfcs around 1.1 in the exposed skin cells, compared to sham exposure. In conclusion, FR2 did not induce DNA-strand breaks or oxidative DNA damage in NHEK and NHEM as most common skin cell types after 4 and 24 h of exposure. Further analyses will amongst others investigate changes in gene expression, epigenetic landscape, micro-RNA expression and telomere length.
Winner of the Best Poster Award at the 10th German Pharm-Tox Summit 2025.