Investigation of frequency response by pulsed electric field on budding yeast for cancer treatment

Pulsed power technology has possibility to be able to provide new method for cancer treatment. Applying a pulsed high electric field with nanosecond duration time onto a cancer cell can induce apoptosis. As the first stage, we have used budding yeast that is a eukaryotic cell, as a model organism of the cancer cell. We investigated the influence on the cell by changing the frequency and field strength of pulse electric field in the experiment. PI and FLICA of fluorescent stain have been used for detecting of cell death and caspase 3/7 activity, respectively. Activity of caspase 3/7 shows that apoptosis is arising in cell. A burst pulse generating equipment with single frequency was used for the experiment. The differences in fluorescence staining at PI and FLICA were investigated at 3.5 MHz with 80 kV/cm and 75 MHz with 120 kV/cm. At the 3.5 MHz, many cell deaths that can be observed by PI occurred immediately after applying the electric field. This result shows that the dielectric breakdown occurs in the cell membrane at 3.5 MHz. Additionally, caspase 3/7 activity was observed simultaneously. At 70 MHz, a little cell death occurred from an hour after applying the pulse. This result shows that the influence to the cell at 70 MHz wasn't the dielectric breakdown of the cell membrane. However caspase 3/7 activity wasn't observed. It is speculated the cell death except dielectric breakdown and apoptosis was induced in the cell at 70 MHz.