Differences in the Effects of Duty Cycle and Interval on Cell Response Induced by High-Frequency Pulses Under Different Pulse Durations

Abstract

High-frequency pulses constitute a new method for tumor treatment and have been proposed to solve the problems of muscle contraction and tumor recurrence caused by the nonuniform distribution of the electric field. However, the killing mechanism of high-frequency pulses remains unclear. Different pulse parameters have varying influences on the killing effect on cells. We studied the influence of the pulse duty cycle and the interval between pulses on the cellular response, including the transmembrane potential (TMP), pore radii, and the pore density, using finite-element simulation. Results showed that, given a pulse duration of $5~\mu \text{s}$ , the pulse duty cycle has an insignificant effect on the cellular response, and the cellular responses under monopolar pulses and bipolar pulses are similar. Given a bipolar pulse duration of 300 ns, the TMP and the pulse radii become larger if the interval between pulses is longer under bipolar pulses. Given a pulse duration of 300 ns, the TMP and pore radii under the monopolar pulse are larger than those under the bipolar pulse. Normal human epidermal cells (Hacat) and tumor cells (Gll19) are used to verify the simulation results, which show that the duty has an insignificant effect on cell killing. The simulation with the duration of 300 ns is verified using an experiment reported in the literature.