## 4 Discussion
Moreover, potatoes were utilized in previous studies focusing on electrochemical EIS-based conductivity analysis [72]. From the non-significant conductivity changes within untreated potato tissue, we conclude that potato tissue is a suitable plant-based model for future EIS-based conductivity experiments to assess PEF effects. However, there may be overall conductivity differences between different potato variants. The cell membrane behaves as a capacitor at low frequencies (around 1 kHz), preventing electric current flow in the intracellular medium. At higher frequencies (10 to 100 MHz), the membrane conducts electric current with similar impedance values for both intact and ruptured cells [73]. During PEF treatment, PEF exerts a force on ions, potentially disrupting membrane integrity and increasing conductivity. This is due to the formation of membrane nanopores, which enhance membrane permeability to Na\({}^{+}\), K\({}^{+}\), Cl\({}^{-}\)[74], and internal Ca\({}^{2+}\) ions move to the extracellular matrix [22; 75]. The higher standard deviation in electrical conductivity observed at lower frequencies in PEF-treated samples may be due to varying intracellular ionic concentrations and differing cellular responses among samples. Electrical impedance tomography (EIT) is a recent technique that adds tomographic capacity to EIS. By a conventional EIT measurement, conductivity maps of (biological) samples at a single excitation frequency can be obtained [76]. Previously, researchers used a 5 kHz excitation signal to obtain in vivo EIT maps of irreversibly electroporated tissue [55]. This study rather recommends an excitation frequency closer to 1000 Hz to image PEF effects using EIT, at least for EIT on potato tissue. In the future, optimal frequencies derived from EIS could be employed for EIT to maximize conductivity differences between PEF-treated and untreated tissue, enabling high-contrast imaging. Our study has limitations. First, we did not examine any time-dependent conductivity changes caused by PEF, but limited EIS analysis to approximately 30 s after treatment. The conductivity of PEF-treated samples is time-dependent. According to the literature, the resealing of pores caused by PEF occurs within 1-100 us, if electroporation was reversible [77]. However, a study using EIS at 3 kHz to analyse the time-dependent changes of high-voltage PEF-treated potato tissue (PV = 4000 V, PW = 1000 us) suggested that conductivity reached a plateau after 50 min [73]. Moreover, PEF treatments with smaller PV or PW may require more prolonged resealing times, ranging from seconds to days [77]. Summing up, 30 s after PEF treatment, tissue damage from IRE was likely to be complete, but conductivity changes may not have reached a plateau yet. Second, our study does not provide an external reference such as tissue staining to assess whether RE or IRE has happened, which is why we refrained from assigning the observed conductivity changes to one or the other regime. Third, EIS is inherently limited because it can only provide localized measurements. Future studies should investigate potential synergies between PEF parameters and explore different PEF treatment electrode configurations, as the current study focused on a single electrode setup and isolated parameter effects. Additionally, nuclear magnetic resonance (NMR) and Raman spectroscopy may be used to characterize extracellular chemical changes, alongside high-resolution confocal microscopy to reveal structural alterations.