Two-Tier Power and Energy Thresholds Governing Discharge Plasma-Induced Cell Death During Molecular and Gene Delivery

This study investigates the mechanism of cell death associated with discharge plasma treatment from the perspective of electrical energy injection, using equivalent circuit network analysis to represent cells, buffer solutions, and well plates as electrical components. Our analysis demonstrated that the observed cell death cannot be adequately explained by a One-Step Model, which assumes that cell death occurs when the total injected electrical energy simply reaches a specific threshold. Accordingly, we proposed a Two-Step Model that explicitly incorporates biological tolerance to external stimuli. In this model, a stimulus accumulates only when the instantaneous power exceeds a primary threshold, and cell death is induced only when this accumulated stimulus surpasses a secondary threshold of energy. The proposed Two-Step Model successfully reproduced the experimental cell death data. These findings suggest that plasma-induced cell death is not a simple physical destruction process governed solely by cumulative energy, but instead reflects a biologically regulated response characterized by a specific power-dependent tolerance. Consequently, this Two-Step Model could provide a theoretical foundation for future optimization of delivery conditions for macromolecules such as messenger RNA (mRNA).