摘要：

Different effects of alternating electric currents (AC) on biological materials have been observed depending on the frequency used. Extremely low frequencies (less than 1 KHz) produce electro-endocytosis at 500 Hz because of membrane depolarization. Intermediate frequencies coincide with tiny particle alignments and cell rotations (also known as the pearl chain effect), thus leading to the tumor-treating fields at 100-300 KHz. High frequencies (i.e., above several MHz) cause tissue heating to predominate due to the dielectric losses. This study investigates how exposure to a wide range of AC electric field frequencies affects the permeability and viability of hepatocellular carcinoma HEPG2 cells. With two silver/silver chloride electrodes, the cells were exposed to a square pulse with a magnitude of 0.4 V/cm at various frequencies between 1 Hz and 1 MHz. A dielectric properties measurement, flow cytometry analysis, fluorescent microscopy, and a polymerase chain reaction (PCR) gene expression analysis were performed. The results showed that all the exposed groups experienced a great reduction in the normal cells, with a clear increase in necrosis and apoptosis compared to the control group. It was noticed that the anti-tumoral effect of the examined frequency range was maximum at 10 KHz and 100 KHz. The permeability was increased in the groups exposed to frequencies above 1 kHz. The viability and permeability results were correlated to the electric relative permittivity, electric conductivity, and gene expression of cyclins A, B, and E.

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