Electroporation of Chlorella vulgaris with laboratory devices capable of generating arbitrary waveform pulses

The influence of pulsed electric fields with different waveforms on the electroporation of Chlorella vulgaris was investigated in this research. A pulsed power generator that can produce high-voltage pulses with arbitrary waveforms was developed. This device was utilized to generate pulsed electric fields of nine different waveforms (rectangle, bipolar rectangle, sine, half-sine, exponential decay, exponential increase, oscillation superimposed on rectangle, two-step rectangle, and triangle) with the same amplitude (17.5 kV/cm) and energy (0.27 J/pulse) for the electroporation of Chlorella vulgaris. The results showed that the pulse waveform played a significant role in the electroporation, which could be explained by the duration of transmembrane potential above threshold Δφth and by the frequent and rapid changes in the electric field above threshold Eth. Among the nine pulses, the oscillating superimposed rectangular pulse and half-sinusoidal pulse had the highest electroporation rate, with an improvement of about 40% compared to the conventional rectangular pulse.