No abstract

The cell membrane permeability, which is strongly related to gene transfection, is improved using a cell-solution electrode for generating atmospheric-pressure plasma (APP) just above the solution. In the case of the floating cells, the cell membrane permeability is significantly improved by the cell-solution electrode APP compared with the conventional diffusion type APP, because the distance between the plasma generation area and the cell solution surface becomes short, which could reduce the radial diffusion loss of the plasma irradiated to the cell suspended solution. In the case of the adherent cells, cell membrane permeability is found to be enhanced by the shorter distance between the solution surface and the adherent cells as well as using the cell-solution electrode, which means that the short-lived reactive oxygen species generated at the solution surface are essential for the improvement of cell membrane permeability.

Despite the promising potential of medical treatments based on non-equilibrium atmospheric-pressure plasma, most of the underlying mechanisms remain unknown.

As factors that influence cell membrane permeabilization during direct and indirect atmospheric-pressure plasma irradiation, charged particle influx, superoxide anion radicals (O2 −∙), and hydrogen peroxide (H2O2) in plasma-irradiated solution were evaluated. These are the three strong candidate factors and might multiply contribute to cell membrane permeabilization. In particular, a shorter plasma diffusion distance leads to the enhancement of the direct effects such as charged particle influx and further increase cell membrane permeability. In addition, O2 −∙ dissipates over time (a life span of the order of minutes) in plasma-irradiated water, and the deactivation of a plasma-irradiated solution in term of cell membrane permeabilization occurs in a life span of the same order. These results could promote the understanding of the mechanism of plasma-induced cell membrane permeabilization.