Development of techniques applying nanosecond pulse electric fields on solid tumor

Bioelectrics has become a notable field of pulsed power application at the present day. Cancer therapy using apoptosis with nanosecond pulsed electric fields (nsPEFs) has been studied in laboratories. We introduced embryonic chick assay to study in vivo. The embryonic chick assay has several advantages and is categorized as in vivo experiment. Many samples can be prepared with low cost by the assay. This study adopted EMT6/KU (mouse breast adenocarcinoma cells) as tumor cells, which formed a solid tumor on the chorioallantoic membrane (CAM) of a fertilized hen egg in the assay. Nanosecond pulsed electric fields with width of 1.5 ns were applied on the solid tumor on CAM with needle electrodes. Stainless wires of 1 mm in diameter were used as the needle electrodes. The two or four needle electrodes were used in this experiment. The solid tumor was dissected and extracted from the egg on a three days after application of nsPEF and was then weighed. The controls of tumor sample were also prepared without nsPEF application. Significance test on the weight of tumors was adopted to determine the effect of nsPEFs application. The difference of weight between the tumor with nsPEF application and control was significantly confirmed. The difference enlarged with the charging voltage of pulsed power generator.