System for nanoporation of biological cells based on optically triggered high-voltage spark-gap switch

Abstract

The nanosecond electric pulse generator based on spark-gap switch which is optically triggered by a 0.45-ns duration and 1-mJ energy laser pulse (wavelength 1062 nm) is designed for electroporation of biological cells suspended in liquid media. The system can also be triggered manually by changing the distance between the spark-gap electrodes. It is able to generate in 75-Ohm impedance transmission line near-perfect square-shape electric pulses (rise and fall times < 0.5 ns) with the duration of 10, 40, 60 or 92 ns. The maximal pulse amplitude is 12.5 kV. The main advantage of the system is the 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 1-mm distance between 28.26 mm2 square disk-shape electrodes was used. The system was tested on human erythrocytes. It was demonstrated that for the 92-ns and 40 ns, duration pulse, the amplitude required to electroporate 50% of cells was 11 kV/cm and 60 kV/cm respectively.