Purpose/Aim
Tumor treatment of irreversible electroporation (IRE) has achieved remarkable curative effect in clinical application. However, due to the limitation of pulse parameters, the region of tumor ablation is small, which cannot be conveniently applied in the treatment of large-size tumors. Recent studies show that high-voltage nanosecond pulse combined with low-voltage microsecond pulse can significantly increase ablation region. In order to study the biological effects of synergistic pulses, a novel topology of the all-solid-state synergistic pulse generator was proposed.
Experimental/Modeling methods
By studying the topology structure, working principle, circuit simulation and prototype test, an all-solid-state synergistic pulse generator with adjustable parameters was developed by using semiconductor switch. The synergistic pulses composed of high-voltage nanosecond pulses and low-voltage microsecond pulses can be output by the flexible control of switches. Besides, further biomedical effects were investigated by the cytotoxicity test, flow cytometry, and monolayer cell ablation experiments.
Results/discussion
The nanosecond pulse parameters were as follows: voltage amplitude of 0-15 kV adjustable, pulse width of 100 ns-1 μs adjustable, current amplitude up to 300 A; meanwhile, the microsecond pulse parameters were as follows: voltage amplitude of 0-5 kV adjustable, pulse length 10-100 μs adjustable, current amplitude up to 100 A.  Carrying out the cytotoxicity test and flow cytometry, the results showed that synergistic pulses had better cell killing effect on Hepa 1-6 tumor cells. Meanwhile, monolayer ablation experiments further confirmed that synergistic pulses could produce larger ablation area with smaller energy.
Conclusions
The development of the pulse generator meets the needs of tumor ablation of synergistic pulses, and lays a hardware foundation for further research on the bioelectrical effect of synergistic pulse and clinical application.

high-voltage pulse generator,semiconductor switch,new topology,irreversible electroporation,biomedical effects