Control of current intensity: Experimental proofs of the relevance of current density in biological cells permeabilisation caused by nanosecond electric pulses

Electropermeabilisation of cells can be obtained by electric pulses of very different durations. In this paper we compare the efficiency of pulses of 100 μs and 10 ns duration eventually in the presence of bleomycin, a cytotoxic drug in order to detect reversible permeabilisation of cells. Biological effects are evaluated using cloning efficiency tests. The impact of the external conductivity is studied for the two types of pulses. Experiments reveal that current density plays a critical role when 10 ns pulses are applied which is very different from the results achieved with more traditional pulses of 100 μs duration.