A Subnanosecond Pulsed Electric Field System for Studying Cells Electropermeabilization

This article presents an experimental arrangement which, using 3-D numerical modeling, aims to study biomedical effects using subnanosecond pulsed electric fields (PEFs). As part of a major effort into developing contactless technology, the final aim of this study is to determine conditions of the applied PEFs (number of pulses, strength, pulse repetition frequency) able to produce electropermeabilization. The arrangement uses a pulsed power generator producing voltage impulses with an amplitude of up to 20 kV on a 50- Ω matched load, with a rise time of 100 ps and a duration of 600 ps. During the preliminary study reported here, samples containing E. Coli were exposed to PEFs in a 4-mm standard electroporation cuvette, allowing the application of a peak electric field strength of up to 60 kV/cm. The studies were facilitated by detailed 3-D electromagnetic modeling of the electric field distribution generated by voltage impulses inside the system. Due to the nature of tests, the numerical analysis played an essential role in the interpretation of results. Preliminary biological results reported in this study are very encouraging, showing that trains of 5000 to 50 000 pulses applied at a pulsed repetition frequency of 200 Hz (maximum PRF) can efficiently induce E. Coli electropermeabilization.