No genotoxic effects but mitotic disturbances found after in vitro THz field exposition of cells

In a project funded by the German Federal Office for Radiation Protection (BfS) two different human skin cell types (HaCaT and HDF) have been exposed under defined environmental conditions to continuous-wave THz radiation at three distinct frequencies of 106 GHz, 380 GHz and 2.52 THz with free-space power densities between 0.03 mW/cm² and 1.96 mW/cm² adjusted traceable to the SI units. In three independent exposition campaigns no genotoxic effects have been found in the micronucleus test and in the comet assay, which have been used as end points. However, accompanying experiments on the production of mitotic disturbances in A_L cells, a human-hamster hybrid cell line, showed that THz radiation at 106 GHz is a spindle-acting agent.