Electroporation (EP) is widely used in medicine, such as cancer treatment, in form of electrochemotherapy or irreversible electroporation (IRE). For EP device testing, living cells or tissue inside a living organism (including animals) are needed. Plant-based models seem to be a promising alternative to substitute animal models in research. The aim of this study is to find a suitable plant-based model for visual evaluation of IRE, and to compare the geometry of electroporated areas with in-vivo animal data. For this purpose, a variety of fruit and vegetables were selected and visually evaluated after 0/1/2/4/6/8/12/16/24 h post-EP. Apple and potato were found to be suitable models as they enabled a visual evaluation of the electroporated area. For these models, the size of the electroporated area was determined after 0/1/2/4/6/8/12/16/24 h. For apples, a well-defined electroporated area was visual within two hours, while in potatoes it reached a plateau after eight hours only. The electroporated area of apple, which showed the fastest visual results was then compared to a retrospectively evaluated swine liver IRE dataset which had been obtained for similar conditions. The electroporated area of the apple and swine liver both showed a spherical geometry of comparable size. For all experiments, the standard protocol for human liver IRE was followed. To conclude, potato and apple were found to be suitable plant-based models for the visual evaluation of electroporated area after irreversible EP, with apple being the best choice for fast visual results. Given the comparable range, the size of the electroporated area of the apple may be promising as a quantitative predictor in animal tissue. Even if plant-based models cannot completely replace animal experiments, they can be used in the early stages of EP device development and testing, decreasing animal experiments to the necessary minimum.

Hepatocellular carcinoma is a leading cause of cancer-related death in many parts of the world. Traditional treatment options are not always effective. During the promising minimally invasive electroporation-based therapies, biological cell membranes are exposed to an external, sufficiently high, pulsed electric field which creates so-called nanopores into the lipid bilayer of the cell membrane. These pores can either be permanent (irreversible electroporation (IRE)), leading to apoptosis, or repairable (reversible electroporation (RE)), with continued cell function. In tumor therapy, RE is used to increase the diffusion of a chemotherapeutic drug during electrochemotherapy. For both IRE and RE, the success of the treatment is dependent on application of the appropriate electric field. Therefore, this study aims to define the pulse parameters and thresholds for IRE and RE on hepatocellular carcinoma (HepG2) cells in-vitro. In a custom-made in-vitro setup, HepG2 cell viability (0, 5, 10, and 15 min), and the peak temperature were measured after electroporation with the different IRE and RE pulsing protocols, to determine the most successful settings for IRE and RE. A CAM/PI flow cytometric assay was performed to confirm cell permeabilization for the RE pulsing protocols with the highest cell viability. The results indicated that an IRE pulsing protocol (70 pulses, 100 µs pulse length, and 100 ms interval) with an electric field strength of 4000 V/cm was needed as threshold for almost complete cell death of HepG2 cells. A RE pulsing protocol (8 pulses, 100 µs pulse length, and 1000 ms interval) with an electric field strength of 1000 V/cm was needed as threshold for viable and permeabilized HepG2 cells. The low peak temperatures (max 30.1°C for IRE, max 23.1°C for RE) within this study indicated that the reduction in HepG2 cell viability was caused by the applied electric field and was not a result of Joule heating.

Purpose: Electrochemotherapy, clinically established for treating (sub)cutaneous tumors, has been standardized in the framework of the European Standard Operating Procedure on Electrochemotherapy (ESOPE). Due to common side effects of chemotherapeutic drugs, recent advances focus on non-cytotoxic agents, like calcium, to induce cell death (calcium electroporation). Therefore, this study aims to determine the efficacy of electrochemotherapy with bleomycin or cisplatin, or calcium electroporation on human hepatocellular carcinoma cells (HepG2) in vitro using the ESOPE protocol. Methods: HepG2 cell viability was measured with a MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay after electrochemotherapy with the chemotherapeutic drugs bleomycin or cisplatin (0–20 µM), or after calcium electroporation (0–20 mM), to determine its efficacy on HepG2 cells in vitro using the ESOPE protocol (8 rectangular pulses, 1000 V/cm, 100 µs) compared to non-electroporated drug treatment. Results: Cell viability was significantly lower in electroporated samples, compared to their non-electroporated controls (27–75% difference). Electrochemotherapy with bleomycin and calcium electroporation, reached (almost) complete cell death (− 1 ± 3% and 2.5 ± 2%), in the lowest concentration of 2.5 µM and 2.5 mM, respectively. Electrochemotherapy with 2.5 µM cisplatin, significantly decreased cell viability to only 68% (± 7%). Conclusion: Electrochemotherapy with bleomycin or cisplatin, or calcium electroporation were more effective in reducing the HepG2 cell viability in vitro using the ESOPE protocol compared to the non-electroporated drug treatments alone. When comparing electrochemotherapy, HepG2 cells are more sensitive to bleomycin than cisplatin, in similar concentrations. Calcium electroporation has the same effectiveness as electrochemotherapy with bleomycin, but calcium potentially has a better safety profile and several treatment advantages. Graphical