Electroporation memory and cumulative transport in yeast cells: Refining the asymptotic model for multi-pulse protocols.

Electroporation (EP) alters cell membrane structure and tissue electrical properties by short and intense pulsed electric fields (PEF). This study addresses the discrepancy between theoretical single-pulse electroporation models and experimental cytotoxicity in yeast cells. EP pore models often fail to predict lethal bleomycin uptake in small cells due to rapid pore resealing. We propose a continuous pore formation model adapted for the 8-pulse ESOPE protocol (100µs, 1Hz). By adjusting the equilibrium pore density parameter (NEQ), the model reproduces "electroporation memory", where persistent pores from preceding pulses facilitate cumulative molecular transport during inter-pulse intervals. Simulations demonstrate that reaching the minimum cytotoxic threshold of 100 molecules depends on electric field amplitude and cell size heterogeneity. At 300kV/m, larger cells (radii of 4-5µm) attain lethal concentrations, while smaller cells radii of 3µm) remain viable. This radius-dependent sensitivity explains the heterogeneous population responses observed experimentally. The findings indicate that multi-pulse protocols ensure efficacy by stabilising pore populations and enabling sustained diffusion. This model provides a quantitative framework for optimising electrochemotherapy parameters in small-cell systems by accounting for cumulative transport and cellular scale variability.