Objective: this work focuses on bleomycin electrochemotherapy using new modality of high repetition frequency unipolar nanosecond pulses.
Methods: As a tumor model, Lewis lung carcinoma (LLC1) cell line in C57BL mice (n = 42) was used. Electrochemotherapy was performed with intertumoral injection of bleomycin (50 μL of 1500 IU solution) followed by nanosecond and microsecond range electrical pulse delivery via parallel plate electrodes. The 3.5 kV/cm pulses of 200 and 700 ns were delivered in a burst of 200 at frequencies of 1 kHz and 1 MHz. For comparison of treatment efficiency, a standard 1.3 kV/cm x 100 μs x 8 protocol was used.
Results: It was shown that it is possible to manipulate the efficacy of unipolar sub-microsecond electrochemotherapy solely by the time delay between the pulses.
Significance: the results suggest that the sub-microsecond range pulses can be as effective as the protocols in European Standard Operating Procedures on Electrochemotherapy (ESOPE) using 100 μs pulses.