System for the Nanoporation of Biological Cells Based on an Optically-Triggered High-Voltage Spark-Gap Switch

This nanosecond electric pulse generator is designed for the electroporation of biological cells suspended in a liquid media. It is based on a spark-gap switch, which is optically triggered by a 0.45-ns duration and 1-mJ energy laser pulse (wavelength 1062 nm). This system can also be triggered manually by changing the distance between the spark-gap electrodes. It is able to generate in a 75- Ω impedance transmission line near-perfect square-shaped electric pulses (rise and fall times ) with durations of 10, 40, 60, or 92 ns. The maximal amplitude of such pulses is 12.5 kV. The main advantage of this system is its ability to generate single pulses, the amplitude and duration of which can be precisely set in advance. To treat the cells, a coaxial cuvette with a 0.03-mL active volume and a 1-mm distance between the 28.3- mm2 circular-shaped electrodes was used. The system was tested on human erythrocytes. It was demonstrated that for the 92- and 40-ns duration pulse, the amplitude required to electroporate 50% of the cells was 20 and 65 kV/cm, respectively.