Nanosecond Pulse Stimulation Immunotherapy And Its Complementary Effects With Microsecond Pulse Ablation

In order to cure cancer completely,many new technologies have been applied in this field.In addition,the therapies based on pulse electric field have shown their unique advantages: non-thermal,non-pharmaceutical,and highly effective.In this thesis,the part relevant mechanisms of the nanosecond pulse stimulation immunotherapy were studied,and the inherent defects of this therapy was found.Accordingly,the complementary effects of nanosecond pulse stimulation immunotherapy and microsecond pulse ablation were proposed.There are three main research contents: the design and manufacture of the digital high voltage pulse system with adjustable parameters;the study on the mechanism of tumor cell apoptosis stimulated by high-voltage nanosecond pulse;the study on complementary effect of intense field microsecond/nanosecond pulse electric field.For the design and manufacture of the digital high voltage pulse system with adjustable parameters,applied with a single cell finite element model,we comfirm that the pulse with the width of 70?s to 100?s,whose electric field energy mainly acted on the cell membrane,could meet the requirements of irreversible electroporation technology.In addition,the pulse with width 100 ns to 1?s,whose electric field energy mainly acted on the intracellular structure,can meet the requirements of nanosecond pulse induction technology.Accorddingly,a nanosecond pulse generator was proposed,whose peak voltage is above 1k V and whose pulse width of 100ns-100?s.To meet this need,we have developed a compact high-voltage pulse generator with a wide pulse width tuning range,based on a capacitor-discharging configuration digitally controlled by a silicon carbide MOSFET switching array and variable capacitance array.The developed digital pulse generator is capable of adjusting: pulse width over 100ns-100?s,voltage over 0-2k V and repetition rate up to 1.25 k Hz.For the study on the mechanism of tumor cell apoptosis stimulated by high-voltage nanosecond pulse,we explored firstly the time window effect,the threshold effect of field strength,and the requirement of pulse dose of nanosecond pulse stimulation.Then,the selectivity of the intense field nanosecond pulse for tumor cells and normal cells has been explored,which depends on the pulse width and the peak electric field intensity.For B16 melanoma cells and L929 fibroblast cells,the pulses with pulse width 300 ns and electric field intensity of 10 k V/cm and the pulses with pulse width 500 ns and electric field intensity of 8 k V/cm pulse electric all process the selectivity,and their direction is opposite.With antibody array and enrichment analysis,the biological and molecular biological processes of the intense field nanosecond pulse electric field stimulation of tumor cells were clarified,and a three-step cascade apoptosis pathway induced by nanosecond pulse was proposed.In terms of the complementary effect of the strong field microsecond/nanosecond pulsed electric field,it was firstly verified that the nanosecond pulsed electric field could trigger the immune effect of animals against melanoma,which could well solve the problems of tumor metastasis and recurrence.However,the nanosecond pulsed electric field could not completely eradicate the tumor cells in the primary lesion.By validating the strong cytotoxicity of the microsecond pulse to the tumor cells remaining after the nanosecond pulse stimulation,it was proposed that the microsecond pulsea and the nanosecond pulsea have obvious complementary effects in the treatment of tumor cells,and the feasibility of the therapy based on their complementary effects is briefly discussed.