Study On Electroporation Of Tumor Cell Membrane Exposed To High Frequency Nanosecond Pulse Bursts Based On Impedance Analysis

Electroporation of cell membranes can cause changes in the impedance of cell suspension or tissue.Analysis of impedance changes exposed to pulsed electric field is helpful to medical personnel to monitor the state of tumor cells in real time.The traditional method to evaluate the effect of pulsed electric field is not convenient.If the quantitative connection between impedance and cell electroporation can be established,only the change of impedance need to be analyzed in subsequent clinical application,and the effect of pulsed electric field can be evaluated without biological detection.As current research method can not conveniently analyze the change of impedance during pulse electric field,and the quantitative relation between the impedance and cell membrane electroporation area is not established,so the impedance real-time change of cell suspension exposed to high frequency nanosecond pulse brusts was analyzed based on measured voltage and current.And the relationship between the cell suspension impedance and cell membrane electroporation area is derived based on the solution equivalent dielectric model.The main achievements are as follows:(1)Based on the pulsed power technology,a high frequency nanosecond pulse brusts generator is developed.Output voltage,pulse burst internal repetition frequency and pulse width of the generator are convenient to adjust.Flow cytometry is used to detect the necrosis rate and apoptosis rate of human melanoma cells A375 under different parameters.The effects of pulse parameters on killing effects are studied,and the pulse parameters used for impedance analysis are determined according to killing effects.(2)After performing wavelet denoising on the measured voltage and current,the values at different frequencies are obtained by FFT.The equivalent circuit of cell suspension is approximated as linear time-invariant,and the cell suspension impedance at different frequencies are obtained through voltage divided by current at corresponding frequency.The Cole-Cole model is used to fit the high frequency resistance R0 and low frequency resistance R?.(3)Impedance analyzer is used to measure impedance before and after exposed,and the error analysis is carried out from absolute value and change rate.The errors of the two measurement methods are acceptable,so the analysis method by use of voltage and current can well reflect the change of cell suspension impedance.(4)Quantitative relationship between the cell membrane electroporation area and impedance is established based on the solution equivalent dielectric model proposed by Maxwell.The changes of cell electroporation area with electric field intensity,pulse burst internal repetition frequency and pulse width are analyzed,and the killing effects are analyzed.