High Intensity Electromagnetic Pulse Source And Study Of Electroporation Effect On Tumor Cells

Three subjects are discussed in this dissertation. To study the electroporationeffects of electric pulses with different waveform parameters, high voltage pulsegenerators are designed and developed, which are capable of generating ps-ns width,100-101kV amplitude pulses. For further exploration of the electroporation effects of theelectromagnetic pulses, ultra-wideband, focused aperture antennas are designed, whichare capable of radiating transient electromagnetic pulses. Adopting the multilayerdielectric model and the equivalent circuit, the waveform parameters with which electricpulses will perforate the plasma membrane or nuclear envelope are quantitativelyanalyze by using some previous experiments data. And related medical experiments arecarried out.With IGBT module, a pulsed generator capable of producing high voltage Gaussianpulses with width300-800ns, continual adjustable amplitude0-5kV and continualadjustable repetition frequency rate1-400Hz is developed to enable research theelectroporation of plasma membrane in medical experiments. Using MOSFET, a pulsegenerator is developed, which is capable of producing high voltage pulses withGaussian rising edge20ns, step adjustable exponential falling edge40-200ns(The stepadjustable half-peak width is50-250ns), continual adjustable amplitude0-1kV, andcontinual adjustable repetition frequency rate0-5kHz. Based on Blumlein forming lineand Photoconductive Semiconductor Switches (PCSS), a high voltage pulse generator isdesigned and developed. It can produce pulses with adjustable width1-5ns, continualadjustable amplitude1-10kV and continual adjustable repetition frequency rate1-1kHz.With avalanche transistors, a pulse generator based on Marx circuit is designed anddeveloped, which can generate adjustable0.2-10ns width,1.2kV amplitude pulses of1-10kHz continual adjustable repetition frequency rate. So, transient electric pulseswith width from sub-nanosecond to microsecond, amplitude from1-10kV are obtainedby the above four pulse generators.The electromagnetic pulse generators based on focusing electromagnetic beam aredesigned in the research aspect of electromagnetic pulses' electroporation effect. One is developed adopting a bow-tie antenna with an elliptical reflector or bow-tie antennaarray, and the other is desiened with a parabolic antenna using a Luneberg-lens focusingelectromagnetic wave.The cell membrane, cytoplasm, nuclear envelope and chromatin of tumor cells areconsidered as lateral homogenous layered medium with different electricparameters(r,), and each cell components is regarded as a equivalent circuit composedof different resistance and capacitance if transient electric pulses are applied. Based oncircuit theory, the voltages on circuit components can be quantitatively analyze whenelectric pulses with different waveform parameters applies on them. The threshold ofwaveform parameters with which electric pulses will perforate the plasma membrane ornuclear envelop are obtained, combined with voltage condition of electroporationreported in previous literature.Considering the influence of transient pulsed electric field distribution onelectroporation effect in suspension, the system simulation calculation is carried outunder different experiment conditions as pulse shapes, capacity, size of needleelectrodes, and relative position, which provides reference data for optimization ofexperimental plan. The apoptosis or necrosis of HeLa induced by nanosecond electricpulses is studied. The relationship between pulse duration and apoptosis isquantitatively analyzed.