Efect of frequency of burst pulse high electric field and burst pulse high intensity electromagnetic wave on microorganisms

Abstract

As applications of pulsed power, there are biological and medical applications, like sterilization, cancer treatment, etc. This work focuses on investigating biological effect of high intensity and high frequency electric field and electromagnetic field on cells. The frequency components applying to those were 25∼70 MHz, and field strength was about 100 kV/cm. The numbers of pulses were 5, 10 and 20. Survival ratios of yeast decreased at all frequency and every number of pulses. At 70 MHz of every number of pulses, survival ratios of yeast were most decreased. The survival ratio of yeast decreased to 30 % at the frequency of 70 MHz on 20 pulses. Meanwhile, a survival ratio of E. coli decreased only 25 % at 70 MHz by applying 20 pulses. In experiment of radiating electromagnetic wave to microorganisms, yeast was exposed to the burst pulse electromagnetic wave with the intensity of 9 kV/cm and the frequency components of 135 and 280 MHz in water. On 100 and 200 pulses, survival ratios of yeast decreased to 70 and 35 %, respectively. For comparison, the pulsed voltage was also applied directly to yeast at same condition of the electric field intensity and frequency components. On 100 pulses, the survival ratio of yeast decreased to 70 % as with the result in electromagnetic wave.