Continuous millimeter-wave radiation has no effect on lipid peroxidation in liposomes

The effect of millimeter waves on lipid peroxidation was studied in the presence and absence of melanin. Irradiation of liposomes with continuous millimeter electromagnetic waves at frequencies of 53.6, 61.2 and 78.2 GHz and incident power densities of 10, 1 and 500 mW/cm2, respectively, did not show an enhancement in the formation of lipid peroxides compared to unirradiated samples. Liposomes exposed to 254 nm UVC radiation at 0.32 mW/cm2 and 302 nm UVB radiation at 1.12 mW/cm2 served as positive controls. No increment in the formation of lipid peroxides was observed when irradiation of liposomes was carried out in the presence of ADP-Fe+3 and EDTA-Fe+3. Direct irradiation of melanin with millimeter waves did not exhibit an increased formation of superoxide or hydrogen peroxide. The present results indicate that millimeter waves of the above frequencies and intensities do not cause lipid peroxidation in liposomal membranes.