Nanosecond electrochemotherapy using bleomycin or doxorubicin: Influence of pulse amplitude, duration and burst frequency.

Electroporation is a pulsed electric field (PEF) induced phenomenon, which effectiveness varies dependent on pulse parameters. This work focuses on nano-electrochemotherapy with bleomycin and doxorubicin to derive protocols as effective as European Standard Operating Procedures on Electrochemotherapy (ESOPE), which employ conventional microsecond range pulses. As a model, murine Lewis lung carcinoma (LLC1) cell line was used. The effects of pulse duration (100-500 ns), PEF amplitude (6-10 kV/cm) and pulse repetition frequency (10 kHz, 100 kHz, 1 MHz) were studied. A total of 75 ns protocol variations have been used. For detection of cell permeabilization, Yo-Pro-1 and flow cytometry were employed. Cell viability was evaluated 24-, 48-, or 72-hours post-electroporation. Nanosecond parametric protocols resulting in comparable treatment efficiency as ESOPE (1.3 kV/cm × 100 μs × 8) have been proposed. It was shown that high-frequency nanosecond electrochemotherapy with bleomycin or doxorubicin could be an alternative for established ESOPE protocols.