The effects and mechanisms of ultrashort and intense pulsed electric fields on biological cells remain some unknown. Especially for picosecond pulsed electric fields (psPEF) with a high pulse repetition rate, electroporation or nanoporation effects could be induced on cell membranes and intracellular organelle membranes. In this work, the design, implementation, and experimental validation of a wideband psPEF exposure system (WPES) is reported, comprising picosecond pulser and wideband biochip, for the in vitro exposure of suspended cells to high-intensity psPEF. Excited by repetitive picosecond pulses (the duration of 200 ps and the amplitude of a few kilovolts), the proposed biochip adopts grounded coplanar waveguide (GCPW) for a wide working bandwidth, which was fabricated with 160 μm thick electrodes for uniform distribution of psPEF in the cross-section. To ensure that only psPEF is generated in the biological medium containing cells except for ionic current, this work proposes to install capillary tubes in the electrode gaps for electrical insulation and cells delivery. By electrical measurements in the time domain and frequency domain, the exposure system is adapted for local generation of extremely high-intensity psPEF with the 3 dB bandwidth up to 4.2 GHz. Furthermore, biological experiments conducted on the developed exposure system verified its capability to permeabilize biological cells under the exposure of high-intensity psPEF.
Keywords: Biochip; Biological cells; Grounded coplanar waveguide (GCPW); Nanoporation; Picosecond pulsed electric fields (psPEF); Picosecond pulser.
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