In recent years, people have been exposed to many kinds of electromagnetic fields (EMFs) generated by domestic electrical appliances and mobile telecommunication devices. There is increasing public concern regarding the health risks of radio-frequency (RF) radiation, particularly that produced by mobile phones. Concern regarding the potential risks of exposure to EMFs has led to many epidemiological investigations, but the effects of EMF exposure on human and other mammalian cells are still unclear. Cellular studies of the effects of RF EMFs have been conducted more often than epidemiological and animal studies. This review provides a summary of the potential cellular effects of RF fields, including those generated by cell phones and their base stations. In vitro studies of the effects of RF fields can mainly be classified into those examining genotoxic and nongenotoxic effects. Genotoxic effects include DNA strand breaks, micronucleus formation, mutation, and chromosomal aberration, i.e., changes involving damage to DNA. Nongenotoxic effects refer to changes in cellular functions, including cell proliferation, signal transduction, and gene expression (mRNA and protein). The results of most recent studies show no marked effects of RF exposure at the cellular and genetic levels. However, some studies have suggested RF effects, and these results require further investigation. As the wireless power transfer technologies are gaining more popularity, it is important that the engineering community participate in the health assessment study with medical and biological research groups. Since the electromagnetic environment due to future wireless power technologies continues to increase, biologists also have to promote the research assessment utilizing advanced technologies in the life sciences. This review paper attempts to provide an insight on the cellular and molecular responses to the RF electromagnetic fields and the understanding of such biological impacts are important for wireless power technology applications.
To investigate the cellular effects of terahertz (THz) exposure, human corneal epithelial (HCE-T) cells derived from human eye were exposed to 0.12 THz radiation at 5 mW/cm2 for 24 h, then the genotoxicity, morphological changes, and heat shock protein (Hsp) expression of the cells were examined. There was no statistically significant increase in the micronucleus (MN) frequency of cells exposed to 0.12 THz radiation compared with sham-exposed controls and incubator controls, whereas the MN frequency of cells treated with bleomycin for 1 h (positive control) did increase significantly. Similarly, there were no significant morphological changes in cells exposed to 0.12 THz radiation compared to sham-exposed controls and incubator controls, and Hsp expression (Hsp27, Hsp70, and Hsp90α) was also not significantly different between the three treatments. These results indicate that exposure to 0.12 THz radiation using the present conditions appears to have no or very little effect on MN formation, morphological changes, and Hsp expression in cells derived from human eye.
Human corneal epithelial (HCE-T) and human lens epithelial (SRA01/04) cells derived from the human eye were exposed to 60 gigahertz (GHz) millimeter-wavelength radiation for 24 h. There was no statistically significant increase in the micronucleus (MN) frequency in cells exposed to 60 GHz millimeter-wavelength radiation at 1 mW/cm2 compared with sham-exposed controls and incubator controls. The MN frequency of cells treated with bleomycin for 1 h provided positive controls. The comet assay, used to detect DNA strand breaks, and heat shock protein (Hsp) expression also showed no statistically significant effects of exposure. These results indicate that exposure to millimeter-wavelength radiation has no effect on genotoxicity in human eye cells.
The potential public health risks of radiofrequency (RF) fields have been discussed at length, especially with the use of mobile phones spreading extensively throughout the world. In order to investigate the properties of RF fields, we examined the effect of 2.45-GHz RF fields at the specific absorption rate (SAR) of 2 and 10 W/kg for 4 and 24 h on neutrophil chemotaxis and phagocytosis in differentiated human HL-60 cells. Neutrophil chemotaxis was not affected by RF-field exposure, and subsequent phagocytosis was not affected either compared with that under sham exposure conditions. These studies demonstrated an initial immune response in the human body exposed to 2.45-GHz RF fields at the SAR of 2 W/kg, which is the maximum value recommended by the International Commission for Non-Ionizing Radiation Protection (ICNIRP) guidelines. The results of our experiments for RF-field exposure at an SAR under 10 W/kg showed very little or no effects on either chemotaxis or phagocytosis in neutrophil-like human HL-60 cells.