Study On Nanosecond High-Voltage Steep Pulse Generator And It's Apoptosis Effect Of Tumor Cells

In order to further research on cell's window and irreversible electrical breakdown (IREB) effect induced by nanosecond pulsed electric field, a nanosecond steep pulse generator that can control the energy of output pulse is developed in this paper. Applied with this generator, a lot of cell experiments were carried out to further validate that nanosecond steep pulse can cause apoptosis of tumor cells.At first, combining traditional pulsed power technology and power electronics technology, a nanosecond steep pulse generator is successfully developed. Produce direct current high voltage by switch power supply, and control this voltage to charge a capacitor through a resistor. Discharge the capacitor to a load after it has charged fully enough fully enough, and this produces an Exponential Decay Pulse (EDP) on the load. No matter in the laboratory as a pure resistance load, or in experiments with cell suspension for load, the fall time of output pulse has reached of 30~50ns. The device is stable, workable and can accurately control pulse energy. Pulse peak 1kV~25kV continuously adjustable; pulse repetition frequency 1~20 Hz continuously adjustable; pulse width adjustable in five levels between 100ns~340ns. These parameters can be adjusted convenient, sensitive, and independent.Then, applied with the device, using self made electrode, a large number of cell experiments on human's ovarian adenocarcinoma SKOVS cells were carried out. We use of MTT observation cell activity, AO/EB fluorescence detection, TEM and SEM observation apoptotic cells on the morphological changes, Observation the effects of apoptotic cells at different electric field intensity by flow cytometry method. Finally, detection the effect on SKOV3 cells'[Ca2 +]i under nanosecond steep pulse and the calcium source when the [Ca2 +]i changes by LSCM.The experimental results show that the level 10kV/cm-100ns steep pulses can induce tumor cell apoptosis. One of the mechanisms of apoptosis may be the increased intracellular calcium ion concentration caused by activation of intracellular calcium stores, thus mediated apoptotic signaling pathway.