Design of electrical characterization method for electroporation-treated biological tissues

The design of a method to evaluate the efficacy of electroporation-treated (with several pulses) tissues is proposed. This method is based on the application of both the standard and a non-standard electrical characterization of biological tissues, on a platform, containing the samples under test, adopted to have minimal invasive contact measurements. Standard direct current electrical characterization was performed for comparison. For the electroporated tissues (using eight pulses), the electrical behavior of the tissue in working condition, governed by high intensity and short duration square wave stimuli, typically used in electrochemotherapy treatments, is utilized. Both electroporation stimuli application and direct current testing were performed using the same electrodes in parallel plate configuration on the parallelepiped shaped samples. The electrodes were not removed during the designed procedure to reduce the interaction with the tissue under test and the effect of different contact resistances. A finite element analysis-based numerical evaluation of the test cell used in the procedure was also performed, both with a constant and an electric field-dependent electrical conductivity, showing its robustness. The method is tested on potato samples, as an example of a biomaterial, whose electrical conductivity is electric field-dependent. The samples were subjected to a high intensity square wave pulse voltage of 100μs long, in order to evaluate the effect of multiple pulses, as a single protocol parameter. Results indicate the dependency of the electrical conductivity on the electric field strength applied using multiple pulses, and the method is easily scalable and usable as a starting point for evaluating the effect of other protocol parameters.